I work with my colleagues on the same project on Windows 7 64 bit version, Visual Studio 2008.
They load JPG and they work. Through QPixmap and Stylesheets. And works. But for me, i can only work with PNG, the rest don´t work at all.
I also tried to change paths on the environment variables, but i only see one Qt path (the bin) on it. Nothing about plugins, i guess... as i read on the documentation:
"By default, Qt can read the following formats: Format Description BMP Windows Bitmap GIF Graphic Interchange Format (optional) JPG Joint Photographic Experts Group JPEG Joint Photographic Experts Group MNG Multiple-image Network Graphics PNG Portable Network Graphics PBM Portable Bitmap PGM Portable Graymap (...)"
I wonder what does "optional" means?.
Your executable is missing the jpg plugin. Optional means, that if your executable doesn't find the plugins (dlls) it will start, but without loading these image formats. It is the same with a lot of qt features (fe: slqdrivers)
You will find the folder "imageformats" in C:\Qt\4.8.4\plugins (replace your installation dir and version), copy it to your executable path and it will show jpgs.
Probably, some environmental variables of your colleagues differ a bit from yours.
Take care with Qt plugins and the distribution of your application.
来源:https://stackoverflow.com/questions/14878670/qt-does-not-load-jpg-just-png