Tell that to the gajillion of Mastodon servers whose TLD is .social. Including mastodon.social which is home to over 20% of all monthly active Fediverse users.

I could have suggested ImageMagick as well, but we’re clearly talking about some who’s just barely scratching the surface on Windows and not about a *nix command line jockey.

As for Windows GUI apps, I’ve got no idea what there is in that field.

• Download and install GIMP on your computer
• Download your images to your computer from your phone
• Open your images in GIMP (you can mass-open a whole lot of them at once from your file manager)
• Scale them down if necessary
• Export them as WebP and/or JPEG, one by one ** Check how big WebP files get when you save them as lossless; save them as lossy only if lossless image files are too big ** If you go for JPEG, try 100% quality first, and don’t go below 90%
• Directly upload these files to Lemmy (that is, I myself, in my personal position, being me and all, wouldn’t necessarily do that on Lemmy)