https://www.patreon.com/posts/how-to-shrink-on-55219008

This tutorial covers shrinking world icons on the World Selection screen so that they appear smaller, which results in less scrolling. Make sure you have followed the setup tutorial here first as I will not be covering setup or finding files. The file we will be editing is GameEntryWorldSelection, and its instance is 240A6D30FCB60E2B.

There are two issues to keep in mind with this method that I couldn’t find a solution for without investing more time, and a third that can be solved but involves more work. The first is that the world images themselves do not shrink along with the icon shape. This means the images are cutoff, and the smaller you go the worse it gets. If you’re only shrinking the icons a bit though, it won’t be that obvious. The second issue is that selecting a world makes the icon increase back to its original size and stays that way until you load into the world, so if you go back to world selection without loading you will encounter this. The third is that the shadows, etc. get left behind the further you shrink. You can adjust these as well to make them match again, but I won’t be covering this (I believe DefineSprite 193 is the best sprite to edit for this).

You can see the issues I mentioned in the image below.

Once the file has loaded, expand the Sprites section on the left and look for DefineSprite (183), which is towards the bottom.

You can also just click the name Sprites and all the available sprites will load at once to the right. Then just scroll down till you find the sprite I mentioned, DefineSprite (183), and double-click to be taken to it, then expand it like in the image above.

Now, we shrink! At the bottom of your screen there are two options you can use. The first is Free Transform, which is similar to any editing program's transform. You can rotate, scale, etc. Unfortunately, there is no way to lock the scaling (that I could find), so if you’re not careful you may end up with an oval shaped icon instead of a circle.

The second option called Edit gives you more control (and correct whatever the transform did), as you can enter numbers manually on the right instead.

I did a mix of both, only adjusting the circle a bit using Free Transform first and then manually fixing what I need to on the right so it’s symmetrical. When done hit Save, then go back to your package and click the Import button on the bottom right. Find the file you just edited, making sure the file type at the bottom right is set to All Filetypes(.) so the .SWF/GFX file shows up in the list. Save the package and move the package into your mods folder if it isn’t already, then load the game.

And looks good so far on my end. You may need to keep adjusting until you get it the way you want, but that's all there is to it.