My app bundle on Mac isn't working on other Macs

Hello !

First of all I noticed the "Deployment" forum but since I'm a complete newbie I thought this is a better place for me.

This is basically the first time I use a Mac. I have no idea how it works, I don't even know if a Qt application is installed by double-clicking it or my draging it to the Application folder or something like that. I developed my entire application on Windows, and I want to make it available on Mac because a lot of my potential users have Macs. I basically copied the source code, installed Qt Creator on a friend's Mac and I opened the project there. On QtCreator, everything works perfectly, but if I try to open the .app folder (created when I compile) on another Mac, nothing, it says that it is not opened because of a "problem".

Of course, I look it up on the documentation, but it only says to use macdeployqt exists. I did. After a few seconds working, the console doesn't display anything but it give me the hand so I guess it worked. But I still can't open it on another Mac. Can you please explain everything to me ? I'm sure that will help a lot of Qt beginners!

And another thing, for displaying my pictures I have to put another folder with the .app and I can't figure out how to add the pictures in the Ressources folder and link to them on my source code. On Windows I did /images/mypiture.png so that's why I have to put the folder with the app, what is the proper way for doing this on Mac (they're all png files).

Thank you very very very much (you're basically saving my life by responding) and sorry for my bad english.
Zougg