Hi all 
Back there with some time for this and some interresting answers 
Thanks to @const @Okidoki and @nezumi.blend for your answers !!!
First of all here’s a light intro on the topic:
Since long ago, i dream of per-image annotations ( i don’t care about annotations evolution along frames ). For my specific use, i need the annotations to change when image changes in UV-IMAGE view. This is what i did here: B3.2: per-image annotations
As you can see, when i change image, the annotation changes according the image. The annotations i have are helpers for texture wrapping in my non atlased global texture. They tell me on what texel i should go back to the other side of the texture.
Unfortunately annotations do not appear on textures in the 3D view. For this i have to change my texture in GIMP and activate my wrapping-points layer wich looks like this:
You can see the red lines ( wrapping lines ) under the blue blender annotations.
The reason why i want to send annotations to image pixels is that it could allow me to throw away my gimp wrap-points layer ( and its manipulations ) and do all in blender 
Note that this process don’t need to be realtime, nor fast at all. It is allowed to take up to, say… 5 sec to run
Now it’s time for me to open python text editor and give a try to this 
I be back soon !
Happy blending !