AppImage icons on Dock

Support & Help Requests
1

One of my apps is showing a default icon with a question mark on the dock. Here is the desktop entry:

[Desktop Entry]
Name=Gravit Designer
Comment=gravit-designer
Exec="/home/user1/Documents/GravitDesigner/GravitDesigner.AppImage" %U
Terminal=false
Type=Application
Icon=appimagekit-gravit-designer
StartupWMClass=Gravit Designer
X-AppImage-Version=3.5.6.2893
MimeType=x-scheme-handler/designer;
Categories=Graphics;
X-AppImage-BuildId=1DhTXVWG6um18L87HmdT90s42nF
X-Desktop-File-Install-Version=0.23
X-AppImage-Comment=Generated by /tmp/.mount_GravitYqKxFJ/AppRun
TryExec=/home/user1/Documents/GravitDesigner/GravitDesigner.AppImage
2

As a workaround, I’d copy the icon(s*) you want to .local/share/icons/ and either name them what’s in the .desktop file ( appimagekit-gravit-designer.XYZ) or change the .desktop file to match your icon’s name.

* If you have multiple sizes, you can make subfolders like 16x16, 32x32 and so on, just make sure the icon files has the correct name.

3

The icon is already in that folder but it’s not showing up on the Dock.

4

I've also got a program that show's the default cog-wheel icon in the mate mutiny-style dock. (In the main menu it has the proper icon.) The program is VeraCrypt, which I installed through the Software Boutique.

I'm afraid that I'd need a more step-by-step walkthrough than the above user, as I'm pretty new to Linux - I don't know where I'd find the 'desktop entry' similar to the one tomasantunes posted. But is it possible to go in and change these icons?

Luke