When posting an image as an attachment, the upload window says that JPG, GIF and JPG are limited to 5 MB or 640x480 pixels.
That's clearly not what happens in practice. PNG images with a width over 640 pixels are resized to 640 pixels and converted to jpg while JPG images are left as is.
examples :
here are 2 PNG images originally in 2268 x 935 resized to 640 pixels wide and converted to jpg by the forum's software.
here are 2 jpg images. The bigger one is 1429 x 2048. The forum's software didn't resize them.
Why are PNG and JPG images treated differently ?
Let's see what happens to this 1081x361 pixels PNG image. (58.67 kb). Edit: resized to 640x214 and converted to JPG. The smaller image (506 x 320) is left alone.
I'm using png images because that's the format Inkscape uses for exporting bitmaps.