I really can only explain it like this: Spectacle saves screenshots correctly and these screenshots can be viewed with Dolphin, Gwenview.. but for exmaple when I try to upload that same file using Chrome it complains, depending on the site, that it's not a valid file, it's size is zero or that it's not the right format. Reproducible: Always Steps to Reproduce: 1. Take a screenshot 2. Try to upload anywhere using non KDE software 3. Errors happen Actual Results: Non KDE software can't open images. Expected Results: Image works fine everywhere. The mime type is fine and here's an interesting bit, if I import the image to Inkscape and export it the image then works.
I cannot reproduce this on my computer. Chromium and GIMP both open the files correctly. Uploading to Imgur also works: http://imgur.com/MCbCIZ3 Spectacle saves images using the standard QImageWriter interface. There's no special magic that happens - so if Spectacle saves images incorrectly, so will other Qt apps. I'd suggest you look at either your Gtk+ or Qt libraries - either of them is incorrectly reading or writing images. Perhaps look at silent disk corruption, too?