What is a "good" size for a map upload?

Hi, I'm new to Roll20 and very psyched about the possibilities of it. I worked to learn it all last week and last weekend my group and I played using it. Although there were times when we struggled with the new (to us) interface we really enjoyed it and looked forward to playing with it more. This week I've been preparing the weekend's game and I've been having a lot of difficulty with map scaling. It seems like no matter how many small sections I cut my map down into it is still too large for the amount of grid Roll20 gives. I'm wondering what is a good size of an image to start with for a map. Currently I'm trying to upload an image that is 630x310 but I'm guessing what is more important is that it's 25 squares wide. I think I read somewhere that 25 squares is the max distance on a Roll20 map, is that correct? Are you allowed more squares if you upgrade to Supporter or Mentor? Anyway, I guess I need to chop this map down even further still in order to make it work. Going to try that. If I'm being obtuse here I apologize and blame frustration lol

To follow up: Chopped the map down a few squares and was able to get the map to scale correctly. Still wondering if there is any way to get maps larger than 25x25.

At the top of your map, there's a little blue dangly-down-y tab, shows all the various maps you have set up. From there, hovering over your choice of maps reveals a little blue geary icon, which holds that particular map's settings. At this point it's trivially easy to resize your map. Note: This does not resize the image. To ensure your map fits the image, and vice-versa, refer to this helpful guide by Gauss. -Phnord

Yes, you can do maps of 50x50, 100x100, or other sizes. And each unit can be any measurement you want. The settings for this are where Phnord explained to look! The translation to your graphics program is, 1 unit = 70 pixels. So however many units you want the map to be, times 70 pixels Height and Width gives you the pixel dimensions to create your background.

Thank you both so much! Had no idea about the blue dangly down thingy with the gear! SO MUCH EASIER NOW! Also, the 70 pixels to a unit is a great help too! thanks!

If you have any further questions feel free to ask. :)

It doesn't have to be 70 pixel though. If you got a premade map that's smaller you can still scale it up in roll20. It will get a little blurry of course. There is a sort of solution for that if it's really bad (But it comes with other issues): Go to the page settings and set the unit size to 0.5, that makes each square just half as big, aka 35 pixels. Now you can have the map smaller, and therefor crispier. But as I said other problems, tokens will look odd sometimes so I wouldn't use that unless it's a really small map and looks really really bad resized. When you have a bigger map though (premade or self) it means you can zoom in more without it getting blurry, so it might be a good idea to make it larger than 70px per square, but that means aligning it is harder.