The first rule of Texture Pain Club is: Save the image you’re painting. If you ‘generate’ an image in Blender, and don’t save it as an external file, it will not save any changes you make to the image when the blend file is closed. I’m probably not the only one that’s put in hours of paint work only to open the file the next day to stare at blank pink walls :mad:
The second rule of Texture Pain Club is: Save the image you’re painting!
Now that that’s out of the way…
Texture Painting can be a messy and cumbersome and sometimes hair-pulling experience, especially for the initiate. A good workflow and organization are key, so you are on the right track mentally.
You can load an image into the brush’s Texture, set its mode to Stencil, and it will enable you to ‘airbrush’ that image across the surface of your geometry. It’s probably not going to give you the most professional results, and takes some trial&error before you get comfortable with it, but once you do it’s a very fast and effective way to cover a lot of surface. And (personally at least) it’s a hell of a lot of fun!
Tips: While in Texture Paint Mode, Shift+F lets you adjust the hardness of your brush. Ctrl+F lets you rotate your stencil (a handy feature I just stumbled across recently!)
There is a lot more you can do with this, but this is the basics to get you started!