XnView Software

Hmm, by the "rules" I meant basically the program behavior - i.e. what type/size/etc. of images is possible to upload via ShellEx. Whether it is a feature that it is possible to send only JPEG via ShellEx or ommision.

That would be nice.

What are the precise rules for ImageShack addon? Sending the file is not available in right click menu on PNG files, but it is present on JPEG files. In XnView it is possible to send both types...

Btw there is a dialog window displayed when I choose to send image to ImageShack ...

Yes, alpha channel was set to 0 for every pixel, so image was completely transparent Just removing alpha channel before conversion to PNG solves the problem.

Hmm, in TweakPNG's internal Viewer when I check 'Use Custom Background Color' image isn't visible (or I should say it is *under* that background it seems). Otherwise it is displaying without problems (without background).

Edit: Hmmm, those pictures don't include an area which should be transparent ...