We've had this circular discussion to exhaustion which is why I have given up hope that IPS will ever get image handling right. It is not fixed. Storing the original image was never a solution for those of us that already had 10's of thousands of images prior to version 4 or from other scripts. All that was ever needed was an option to not reapply the watermark when rebuilding the images (ie if you wanted to change thumbnail sizes). Not only did the storage of the original image increase the storage overhead significantly for those of us that didn't need or want that option, it did not address the legacy image rebuild problem.
In the past this rebuild feature did not have an option to rebuild without watermarks. So if you had images that were imported from other programs or watermarked in earlier versions of IPgallery, a second watermark would be applied over the first, irreversibly damaging all the images in the gallery. I'm hoping this has changed as I would characterize this as extremely negligent on the part of IPS (especially in light of the fact this was pointed out for years and nothing was ever done about it).
And yes just having a thumb and a larger view should be considered the most basic gallery functionality and any other configuration (multiple images) should be options in the software.
To be honest, with the number of years that have passed with the gallery ranging from a buggy mess to a complete disaster, I'm losing hope that IPS can actually create a reasonable gallery program, which is baffling considering everything else they make is pretty good.