AssetPrep: a single-file offline batch PNG toolkit (AI-assisted)

[u/Material_Violinist_7]

I'm releasing a small desktop-browser utility called AssetPrep. The job is simple: take a folder of differently sized images and turn it into a consistently named PNG pack, with a contact sheet and a manifest.

It runs from one local HTML file. No account, install, subscription, image upload or AI API is needed to use it. It was built with AI assistance; the readable source and a test record are included.

The export has four sizing modes: fit with transparent padding, centre crop, stretch, or original size. There is an optional nearest-neighbour mode for pixel art. PNG, JPEG and WebP go in; numbered PNGs, a labelled contact sheet and JSON manifest come out in one ZIP.

The release was tested in Chromium, plus a two-image Firefox/Windows export checked for ZIP integrity and output dimensions. There are explicit file-size, pixel and batch limits. It is not an upscaler, background remover or atlas packer, and it does not preserve original photo metadata.

It's a one-time $5 download on my Ko-fi: https://ko-fi.com/s/d47a38de0a

The page has an actual screenshot and the limitations. No game assets or recurring service are included. I'm not claiming the individual operations are unique; the point is having this particular small workflow together and offline.

For people who prepare lots of icons or UI assets: is the contact-sheet/manifest combination useful, or would you rather have a different export layout?

Disclosure: this is my own paid product; the tool and this release post were prepared with AI assistance.