better GUI tools

Currently, the GUI tools are a pain to use, especially regarding images.  Here are some things we could improve on: 

RIght now when you import an image, you need the image to be the perfect size, and there is no resizing.  Plus, if it is too big, it turns tiny, which is odd and annoying.  I usually have to split the GUI into four, which is kind of ridiculous.  I think you need to have at least a resize tool for the images. 

You could also improve with the ability to change button size, and to change the button color as well. 

Another improvement would be being able to select which slots you want to hide, and maybe even edit the texture of the slots/buttons.

A duplicate tool would save a lot of time.  It's a pain in the butt to have to edit the settings for every single button or slot you add, especially when your GUI includes a whole bunch of them.  I think being able to duplicate them would solve this issue quite nicely.  

Adding support for a scroll wheel would be ideal.  Think about how the villager GUI functions.  There are many trade buttons not all of which can fit on one GUI.  I believe the best way to fix this is a scroll wheel.  You can just scroll down and see more trades.  

Gif support.  Do I need to say any more?  Furnace has the progress bar and the fuel counting thingy, and I think it would be nice to have that available.  Maybe have a procedure hooked up to it to tell it when to play the animation?  

I think I speak for everyone when I say every one of these features would make GUIs a great deal better.  Thank you for reading.