I just made a post copy-pasting images from another tab. All jpegs became pngs, for example 1.3MB became 6.4MB.
If I save the image first, then upload to Lemmy, it stays as a jpeg. What causes the pointless converting when copy-pasting? Can it be stopped from happening?
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.
In Firefox I right-click the image and select “Copy”. In the same window in the other tab I hit Ctrl-V.
Surely it sends the file from the local cache folder?
No. When you copy an image like that you’re copying the image data to your clipboard, not the file.