libretro-thumbnails VS caesium-image-compressor

I've been trying to pretty up my collection by making sure everything is validated and has the appropriate boxart. About the only things i've had problems with are the Sharp X86000 and NEC-PC98. These have named boxarts/etc found in the libretro git but I can't seem to find any corresponding dat file to link any particular romset with the retroarch database. Has anyone else dealt with this?

I tested this in Chrome with the entire Sega Mega Drive collection (2075 images) from libretro-thumbnails and it took about 5 minutes on my ageing laptop.

On my RetroArch on PC based on Linux the thumbnails are in a subfolder named "thumbnails" in main RetroArch folder. Each system has folders as "Named_Boxarts", "Named_Snaps" and "Named_Titles". Manually downloads could be done in example at https://thumbnails.libretro.com/ or one of the repos in https://github.com/libretro-thumbnails?q=mame&type=all&language=&sort= or in one of the the subfolders in https://github.com/libretro-thumbnails/libretro-thumbnails

I know this one, if that is what you mean: https://github.com/libretro-thumbnails On this page if you click "libretro-thumbnails" and then "MAME" in example, then it is a bit older than if you go straight to the "MAME" repository itself. I guess one is the master that collects all other repositories after a while. But that's just my theory. As far as I know is this the official thumbnails repository for Libretro/RetroArch.

Retroarch just matches console and game name to the artwork it stores on its own github page.

If you'd like to submit the ones you've collected, you can send a pull request to https://github.com/libretro-thumbnails/libretro-thumbnails

Also for artwork check https://github.com/libretro-thumbnails/libretro-thumbnails

I use this: https://saerasoft.com/caesium

I also use Caesium Image Compressor on my ROMs and Themes folder to reduce their size and improve the RG35XX's responsiveness.

If you want further compression you could check out Caesium Image Compressor which is free (and I'm not affiliated with it incidentally, I just like it).

Try an image compression tool, this one is free and open source: https://saerasoft.com/caesium/

Amazing, free and open-source: Caesium.

I'm new to AppImage creating. (sorry I'm not a native English speaker) I was trying to create an AppImage for this Caesium Image Compressor (Qt6). Failed to find a way to do that. Qt6 is too new for AppImage?

Caesium Image Compressor can do the job and it is easy to use. There is also imagemagick which is basically the swiss-knife for image editing, but based on you having looked for websites first, I assume you don't look for a commandline tool (imagemagick is a commandline tool).

Caesium image compressor: https://github.com/Lymphatus/caesium-image-compressor and Imagine: https://github.com/meowtec/Imagine