why do icons only show up on my computer ??

[d_stranz]

Try converting one of your ico files to png and make sure the png file is added to the qrc resources and compiled into your program. I do this for all of my toolbar icons and do not need to deploy any image handling plugins with my app. Works just fine on a PC with no Qt installed, just the few DLLs that my app needs installed in the app directory along side of the EXE file.

I have not tried to use an ico file directly, since I get most of my icons in png format. Your problem could be as simple as not having the file built into the resources, but I would try the png conversion first.

[ZikO]

@d_stranz. Hi. Do you think there is a problem with rendering icons via ICO files? I am using the same *.ico file for Desktop, windows title, and system tray icons. In my machine, everything works well (Win 7 64bit). On another machine where Qt is not installed, what I know is that system icon is not rendered but all the other looks correct.

[ChrisW67]

The icon (*.ico) you have embedded in Windows resources for display as the application icon is read and interpreted by Windows not Qt. This is why it displays correctly in Windows contexts (desktop, task bar).

That same *.ico file requires the ICO image format plugin in order for Qt to display it. PNG files work out-of-the box because their processing is built in, other formats (GIF, JPEG, ICO, TIFF, MNG) require a plugin that is loaded (if available) on program start or demand. Dependency Walker (DW) will show you the libraries that are early-bound to the executable, i.e. known to be required up front, when you open the executable. If you run the executable in DW profiling mode you may see other libraries pulled in dynamically. I do not think you will see failures to load the ICO image format plugin because Qt only attempts to load the plugins it finds. On your dev machine the plugins are present and the *.ico file can be displayed by Qt. If you deploy without the relevant image format plugins then the deployed system will be unable to display images of that format: displaying a blank space instead of crashing.

The solution is simply to create a folder called imageformats next to your deployed executable and place qico4.dll in that folder.
Here is an example layout