1. undo the image size restrictions
2. undo the force to upload a thumbnail. At the old gallery a thumbnail was created automatically if none was uploaded.
3. don`t delete everything one has entered on the upload page if one has made a mistake or forgot something so one has to enter all new.

but mainly I criticize the upload restrictions for image size. Old images of my gallery are still huge, why new uploads have to be smaller? That makes no sence to me.

The look of the site, well that is not so bad, but as many others have written. Most of us using widescreen monitors and PCs or labtobs with widescreen monitors and not phones or tablets. If you want to be also on phones and tablets, create a phone and tablet suitable side nexto the original site. I think we all have spend enough money at the store so money can`t be a problem.