Topic category: Feature requests and ideas for MCreator
It would be awesome to make certain images act like other things, such as item slots or buttons, without having to stick to the original format. I know item slots already can be colored, but it would be awesome to have custom images within the item slot like the dye or banner slots on a loom, or to just be able to have better or more custom looking buttons than the text format one provided (For instance be able to make arrow buttons for switching GUI pages instead of having to type a ">" and live with that being your arrow button. It would also be nice to be able to animate some things better, for instance making "gliding" mechanics instead of having to make eleventeen thousand different images and putting them all in the path of its glide and making a bunch more procedures with certain conditions just to get one gliding affect. It would be so much better if you could say something like: If procedure=true, glide to X:___, Y:____. It would also be nice to make some animated textures only animated on certain conditions, kind of like "costumes" in programming, to where its still the same image, but they don't only display on certain conditions. (like the flames of a furnace fire, or even outside of GUIs, the loading of a crossbow, ETC)
TL;DR
Make more customizable GUIs
You can customise a GUI in resources. Every time you create a GUI mMCreator generates an images in resources that you can modify. If you modify the GUI, this image will be restarted so only modify an GUI image if you are sure you have ended working on it.
Building on what Danitosaurio said there is actually a tutorial here on the MCreator forum that shows you how to have image buttons! There are some code modifications you need to make for it to work in 1.18 but they are pretty simple, and I could do it and I don't even know how to code yet! See the tutorial here: https://mcreator.net/forum/83507/added-image-buttons-guis