tile
This happened when the UDIM tiled image needed to be colormanaged, so
- when you set up the image as sRGB, then save as EXR/HDR/...
- other way around as well: when you set up the images as Linear then
save as PNG/JPG/...
Reason being that for UDIM tiled images, `image_save_single` is called
multiple times [once for each tile] and everytime `image_save_post` will
fire the `IMA_SIGNAL_COLORMANAGE` signal which clears the cache if any of
the above two is the case. Without the cache, the next tiles cannot be
saved.
Now determine if the colorspace changed from
`image_save_single`/'image_save_post' and only fire
IMA_SIGNAL_COLORMANAGE once from BKE_image_save in the end.
(thx @brecht for suggesting this alternative to the original fix)
Maniphest Tasks: T75234
Differential Revision: https://developer.blender.org/D7296
029a714fc7