This app is not a 1-star app, despite what other reviews may say. It does what it says and works fairly reliably. With that said, there are definitely improvements I would like to see the developer implement.
First, the things that really NEED to be changed...
It only works in portrait orientation. An educational app like this really needs to work in landscape orientation so it can be set in a stand or displayed to a class.
The displayed images are pretty tiny. Again, for an educational app, the images should be as large as possible - preferably full-screen or close to it. In a classroom environment, unless used with a projector or very small group of students - even on a full-sized 10+” iPad - anyone sitting more than a few feet from the teacher can have a hard time recognizing anything other than the most basic shapes and colors.
Next, things I’d LIKE to be changed...
Add gif support. Was very disappointed I made a bunch of custom prize-box gifs for a lesson that would reveal the contents - only to have this app only display the very first, single, static frame.
Allow us to hide the images. Either a transparency/blur effect, or just a set image or colored box to cover the images used. This would allow more flexibility in using this as an educational tool.
Lastly, the app seems to crop images to square. Would be very nice if it allowed for something closer to a 4:3 or 16:9 ratio that most modern digital images are designed for.
TLDR: In short, the app works and does what it claims. Sadly, not many apps on the store offer this function, so - for @$1 - it’s a decent, but far from polished, app. But in its current form it seems more like something built as a hobby or proof-of-concept rather than an actual educational tool. I would very much like to see some of the recommended improvements made to this app.