About This File
LaunchBox Precache Manager (LPM) V.1.0 PS (powershell version)
Mass image optimizer + precache system for LaunchBox libraries (PowerShell 5.1, ASCII-only).
TL;DR
LPM scans your LaunchBox Images folder, builds a compressed WebP/JPEG precache into:
LaunchBox\Images\_Precache
…then (optionally) swaps your original image folders for the precache using NTFS junctions.
Original art is protected in: Images\_Originals
LaunchBox/Big Box browsing gets faster and lighter
You can restore originals at any time
Designed for very large libraries (hundreds of thousands to millions of images).
What’s included
This package contains two main scripts:
LB-Precache-Manager.ps1 – interactive front-end menu (the “manager”)
Build-LaunchBox-Thumbnails-Parallel.ps1 – the “engine” that does the heavy lifting
Optional (recommended):
cwebp.exe – Google WebP encoder (best compression / speed)
Launcher:
Launch-LPM.cmd (optional convenience)
You can also run the manager directly with PowerShell.
High-level workflow
Audit your Images folder (counts, types, savings estimates).
Build thumbnails (create/update files in Images\_Precache).
Backfill later (fill gaps only after partial runs or new content).
Activate Precache (parks originals into _Originals, junction-swaps to _Precache).
Restore Originals (undo junction swap, put everything back).
Rebuild existing precache later with a new profile if you want tighter compression.
Important notes up front
Close LaunchBox and Big Box before running (especially Activate/Restore).
Locked folders will be skipped.
Back up first.
Make a backup/snapshot of your LaunchBox folder if you’re cautious (recommended for first-time users).
LPM does not change your game metadata except when you explicitly use:
Clean XML references (only removes references to images already moved to _BadImages).
Remote / network / external path warning (important)
LPM is built for local, fixed disks.
If your LaunchBox path is a mapped drive / UNC path / remote share, some operations will refuse to run and you will see:
Remote paths not supported; run on the Launchbox PC.
This prevents multi-day failures, broken junctions, and extreme slowdowns.
SAFE vs FULL run mode
At startup you’ll choose a run mode:
SAFE: low impact (older/USB systems)
FULL: uses hardware recommendations for faster multi-threaded work (best on SSD/NVMe)
FULL mode will also show detected hardware and recommended defaults (workers/batch sizing).
Why counts don’t always match
It’s normal to see differences between:
a simple file count script, and
what the engine prints during scanning/building
Reasons:
The engine may walk additional internal paths (depending on mode and what already exists in your Images tree).
“Visited directories” and “files matched” are progress counters, not a strict “real folder count.”
Bottom line: don’t panic if counts don’t line up perfectly, especially after multiple runs or after Activate/Restore operations.
Handling locked folders / “file in use”
During Activate/Restore (and sometimes builds), you may see locked items skipped.
What it means:
LaunchBox/Big Box/Explorer/AV has something open.
What LPM does:
prints a warning
continues with the rest (doesn’t abort the entire run)
Fix:
close LB/BB
re-run the option (safe to re-run)
Installation
Extract the zip anywhere (Desktop/tools folder).
Run one of:
Launch-LPM.cmd (recommended convenience)
or open PowerShell and run: .\LB-Precache-Manager.ps1
Recommended:
Run PowerShell as Administrator for:
junction swap operations
optional Defender exclusion
standby-cache clearing (RAM file cache)
Logging
LPM supports two concepts:
1) Feature state (always-on)
LPM-Answers-Last.json
This stores the last answered prompts so you can re-run the same build easily (Repeat mode uses this).
This is NOT a log and remains on by default.
2) Session logs (optional)
You may be asked early in startup whether to disable session logs.
Default: logs enabled
If disabled: fewer files written; console output still appears
Batch mode also maintains small state/summary files so it can resume safely.
Main Menu (Manager)
You’ll see:
Main Menu
[0] Audit images (recommended first step)
[1] Build Thumbnails
[2] Activate Precache (junction swap)
[3] Restore Originals
[4] Clean XML references
[5] Backfill missing precache from Images
[6] Rebuild existing precache at new profile
[7] Exit
[B] Batch run-all (50,000 cap per session)
[R] Repeat last build (use saved answers)
[T] Clean LPM temp files (optional)
[0] Audit images
Walks the Images tree and produces:
counts
convertible totals
rough space saving estimates
planning hints per profile
Outputs:
lb_audit.json
lb_audit.csv
[1] Build Thumbnails
Creates/updates the precache under:
LaunchBox\Images\_Precache\...
Profiles:
Fast
Balanced
Extreme
Custom
Notes:
If cwebp.exe is present, WebP is used (best compression).
You can force JPEG-only (optional).
[2] Activate Precache (junction swap)
“Turns it on.”
Moves originals to Images\_Originals\...
Creates junctions under Images\... pointing to _Precache
[3] Restore Originals
Undoes Activate:
removes junctions
moves originals back from _Originals
[4] Clean XML references
Advanced/optional cleanup for broken image refs linked to _BadImages.
[5] Backfill missing precache from Images
Fills only what’s missing:
finds originals without corresponding precache output
generates precache copies only for those
[6] Rebuild existing precache at new profile
Re-encodes existing precache using a different profile (only replaces when beneficial, depending on settings).
[B] Batch run-all (50,000 cap per session)
This is for huge libraries with hundreds+ platforms/folders.
What it does:
Iterates through platform folders under Images
Processes them in segments capped at 50,000 per batch session
Writes output into: Images\_Precache\<Platform>\...
Can resume where it left off in later runs using a state file
Behavior:
Prompts per platform with an auto-default (so you can run unattended)
Designed so you can run overnight without bogging down the machine for days in one “run all”
Batch state:
LaunchBoxRoot\LPM-Batch-State.json (resume point / continuation)
Batch summary:
Writes short progress summaries to the LaunchBox root (easy to find)
Also:
Batch runs can clear standby cache automatically (admin required) before segments to reduce cache thrash.
[R] Repeat last build (use saved answers)
Re-runs your last answered configuration using:
LPM-Answers-Last.json
This is the “do exactly what I did last time” option.
[T] Clean LPM temp files (optional)
Cleans LPM temporary working files (typically under Windows %TEMP% related to LPM processing).
This is safe housekeeping and does not change your LaunchBox Images content.
Notes about WebP + LaunchBox
LaunchBox can display WebP files when they’re in place in the Images tree, but:
Drag/drop and scraping workflows typically expect PNG/JPG sources.
LPM’s approach keeps originals safe, while precache improves performance.
Clear Logos:
PNG sources are strongly recommended (transparency matters).
Recommendation for first-time users
Run Audit
Run Build Thumbnails with Balanced
Test LaunchBox/Big Box performance
Then consider Activate Precache
Support / community
Let me know below if you have suggestions for improvement, or if you dfind something that doesn't work as intended.
If you like this and want to help me out, buy me a coffee 
https://buymeacoffee.com/mcflylpm
Edited by -McFly-
updated the readme
What's New in Version 1.0 PS See changelog
Released
LaunchBox Precache Manager (LPM) V1.0 PS (powershell version)
Mass image optimizer + precache system for LaunchBox libraries (PowerShell 5.1, ASCII-only).
TL;DR
LPM scans your LaunchBox Images folder, builds a compressed WebP/JPEG precache into:
-
LaunchBox\Images\_Precache
…then (optionally) swaps your original image folders for the precache using NTFS junctions.
-
Original art is protected in:
Images\_Originals -
LaunchBox/Big Box browsing gets faster and lighter
-
You can restore originals at any time
Designed for very large libraries (hundreds of thousands to millions of images).
What’s included
This package contains two main scripts:
-
LB-Precache-Manager.ps1– interactive front-end menu (the “manager”) -
Build-LaunchBox-Thumbnails-Parallel.ps1– the “engine” that does the heavy lifting
Optional (recommended):
-
cwebp.exe– Google WebP encoder (best compression / speed)
Launcher:
-
Launch-LPM.cmd(optional convenience)
You can also run the manager directly with PowerShell.
High-level workflow
-
Audit your
Imagesfolder (counts, types, savings estimates). -
Build thumbnails (create/update files in
Images\_Precache). -
Backfill later (fill gaps only after partial runs or new content).
-
Activate Precache (parks originals into
_Originals, junction-swaps to_Precache). -
Restore Originals (undo junction swap, put everything back).
-
Rebuild existing precache later with a new profile if you want tighter compression.
Important notes up front
-
Close LaunchBox and Big Box before running (especially Activate/Restore).
Locked folders will be skipped. -
Back up first.
Make a backup/snapshot of your LaunchBox folder if you’re cautious (recommended for first-time users). -
LPM does not change your game metadata except when you explicitly use:
-
Clean XML references (only removes references to images already moved to
_BadImages).
-
Remote / network / external path warning (important)
LPM is built for local, fixed disks.
If your LaunchBox path is a mapped drive / UNC path / remote share, some operations will refuse to run and you will see:
Remote paths not supported; run on the Launchbox PC.
This prevents multi-day failures, broken junctions, and extreme slowdowns.
SAFE vs FULL run mode
At startup you’ll choose a run mode:
-
SAFE: low impact (older/USB systems)
-
FULL: uses hardware recommendations for faster multi-threaded work (best on SSD/NVMe)
FULL mode will also show detected hardware and recommended defaults (workers/batch sizing).
Why counts don’t always match
It’s normal to see differences between:
-
a simple file count script, and
-
what the engine prints during scanning/building
Reasons:
-
The engine may walk additional internal paths (depending on mode and what already exists in your Images tree).
-
“Visited directories” and “files matched” are progress counters, not a strict “real folder count.”
Bottom line: don’t panic if counts don’t line up perfectly, especially after multiple runs or after Activate/Restore operations.
Handling locked folders / “file in use”
During Activate/Restore (and sometimes builds), you may see locked items skipped.
What it means:
-
LaunchBox/Big Box/Explorer/AV has something open.
What LPM does:
-
prints a warning
-
continues with the rest (doesn’t abort the entire run)
Fix:
-
close LB/BB
-
re-run the option (safe to re-run)
Installation
-
Extract the zip anywhere (Desktop/tools folder).
-
Run one of:
-
Launch-LPM.cmd(recommended convenience) -
or open PowerShell and run:
.\LB-Precache-Manager.ps1
-
Recommended:
-
Run PowerShell as Administrator for:
-
junction swap operations
-
optional Defender exclusion
-
standby-cache clearing (RAM file cache)
-
Logging
LPM supports two concepts:
1) Feature state (always-on)
-
LPM-Answers-Last.json
This stores the last answered prompts so you can re-run the same build easily (Repeat mode uses this).
This is NOT a log and remains on by default.
2) Session logs (optional)
You may be asked early in startup whether to disable session logs.
-
Default: logs enabled
-
If disabled: fewer files written; console output still appears
Batch mode also maintains small state/summary files so it can resume safely.
Main Menu (Manager)
You’ll see:
Main Menu
[0] Audit images (recommended first step)
[1] Build Thumbnails
[2] Activate Precache (junction swap)
[3] Restore Originals
[4] Clean XML references
[5] Backfill missing precache from Images
[6] Rebuild existing precache at new profile
[7] Exit
[B] Batch run-all (50,000 cap per session)
[R] Repeat last build (use saved answers)
[T] Clean LPM temp files (optional)
[0] Audit images
Walks the Images tree and produces:
-
counts
-
convertible totals
-
rough space saving estimates
-
planning hints per profile
Outputs:
-
lb_audit.json -
lb_audit.csv
[1] Build Thumbnails
Creates/updates the precache under:
-
LaunchBox\Images\_Precache\...
Profiles:
-
Fast
-
Balanced
-
Extreme
-
Custom
Notes:
-
If
cwebp.exeis present, WebP is used (best compression). -
You can force JPEG-only (optional).
[2] Activate Precache (junction swap)
“Turns it on.”
-
Moves originals to
Images\_Originals\... -
Creates junctions under
Images\...pointing to_Precache
[3] Restore Originals
Undoes Activate:
-
removes junctions
-
moves originals back from
_Originals
[4] Clean XML references
Advanced/optional cleanup for broken image refs linked to _BadImages.
[5] Backfill missing precache from Images
Fills only what’s missing:
-
finds originals without corresponding precache output
-
generates precache copies only for those
[6] Rebuild existing precache at new profile
Re-encodes existing precache using a different profile (only replaces when beneficial, depending on settings).
[B] Batch run-all (50,000 cap per session)
This is for huge libraries with hundreds+ platforms/folders.
What it does:
-
Iterates through platform folders under
Images -
Processes them in segments capped at 50,000 per batch session
-
Writes output into:
Images\_Precache\<Platform>\... -
Can resume where it left off in later runs using a state file
Behavior:
-
Prompts per platform with an auto-default (so you can run unattended)
-
Designed so you can run overnight without bogging down the machine for days in one “run all”
Batch state:
-
LaunchBoxRoot\LPM-Batch-State.json(resume point / continuation)
Batch summary:
-
Writes short progress summaries to the LaunchBox root (easy to find)
Also:
-
Batch runs can clear standby cache automatically (admin required) before segments to reduce cache thrash.
[R] Repeat last build (use saved answers)
Re-runs your last answered configuration using:
-
LPM-Answers-Last.json
This is the “do exactly what I did last time” option.
[T] Clean LPM temp files (optional)
Cleans LPM temporary working files (typically under Windows %TEMP% related to LPM processing).
This is safe housekeeping and does not change your LaunchBox Images content.
Notes about WebP + LaunchBox
LaunchBox can display WebP files when they’re in place in the Images tree, but:
-
Drag/drop and scraping workflows typically expect PNG/JPG sources.
-
LPM’s approach keeps originals safe, while precache improves performance.
Clear Logos:
-
PNG sources are strongly recommended (transparency matters).
Recommendation for first-time users
-
Run Audit
-
Run Build Thumbnails with Balanced
-
Test LaunchBox/Big Box performance
-
Then consider Activate Precache
Support / community
Let me know below if anything doesn't work, or suggestions for future improvement.
If you like this and want to help me out, buy me a coffee:
https://buymeacoffee.com/mcflylpm
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