Alamy havent been rejecting the full submission on finding faults (unless its your approval one) for over 1.5 years. I send a full DVD at a time with about 350 images on them, only had 51 rejected out of 35,000 ish. Of which all passed on resubmission, 90% of them being Alamy not being able to open the image, most of the time an Alamy problem, not mine.
Good advice is clean every image at 100%, dont submit images which are very soft / lacking definition, if using a MAC save in PC byte format.
I always sharpen a little on conversion from RAW to TIFF, to just give it a little, Do all your keywords and description fields before sending them in as it saves loads of time, and when Alamy have them up for you to licence its just a 2 min job not hours.