This seems to be a Javascript thing, not a Lemmy thing. IIRC, everything that's pasted triggers the onpaste event with a "image.png" file/blob, regardless of the source format.

Hi,

this is done by pict-rs ( the image hosting middle man that lemmy uses ) it converts every image uploaded to png. Only way of keeping a jpg is using a external image hoster ( like imgur ) and just embeding the link here.

Thanks

Are you pasting the file or the image data?

If you’re opening the image, and copying the file’s contents, I could imagine it becoming uncompressed bitmap data to be stored on the clipboard rather than the clipboard containing lossy compressed image data. When pasting the contents somewhere, you can’t count on the destination handling jpeg data as often/reliably as you can count a destination being able to handle bitmap data.

edit: I hit the wrong reply button, but I guess this stands alone fine as it is.

What OS are you using? Perhaps it’s being converted because of limitations of the clipboard?

Probably because a PNG takes up less storage space.