In the previous article I have mentioned the potential issue with some uploaded images hanging in state "Processing image" for surprisingly long time after upload and expressed hope that there is some background "catch it all" process that would take care of all these. As it turned out, there is. All uploaded images that were haging in the processing stage turned up to be fixed by next day or so (it was about 10-20 images out of about 3-4 thousand).
Here is a simple trick how to make sure it is indeed so. After uploading a gallery, tag every image in processing with some distinctive tag, e.g. "checkme". Regardless in how many galleries, categories or subcategories your images will be, you will show them all by clicking on the checkme tag in your home page. After verifying that the images are OK, you can use bulk edit to remove the tag from all.