Collapse many assets in roll20 map to help performance?

As the topic says i love using the many marketplace assets that are available. I would like to know if there is a way to collapse all the assets into 1 large image to help the performance of the game. Because i use dynamic lighting with many assets some of my maps are quite laggy.

Use an outside program like Gimp or Photoshop and import it back in. Many market place assets can be downloaded.

Hey Taran! Many people, myself included, use marketplace assets to build maps outside of Roll20 and then save them in as a single image. Many marketplace creators allow you to download the art that you have purchased so that you can install it on your hard drive. Programs like Photoshop, Gimp and Dungeon Painter Studio are the ones that I think are most commonly used to make the maps. My personal preference for fast encounter map making is Dungeon Painter Studio.  Another option that I haven't tried myself, is to build your map in Roll20 and then take a screenshot of the finished product. You can then upload it as a single image into your Roll20 library.

Thanks for the replies! i was thinking about doing that i do have dungeon painter studio but i cant get the assets to load properly so i will have to mess with it more. I was also hoping that i might just be able to do it on roll20 for ease :P but thanks guys.

Dungeon Painter Studio is a little finicky and does not have all of the functionality of GIMP or Photoshop, but it's great for quick and easy map building. When you add an asset, try to make it the size suggested by the marketplace creator if they have given unit dimensions, which a lot of them do. I find a lot of the backgrounds (like grass or snow) that are sized over 10 units can be a bit of an issue to get in as they don't size properly. If you'd like some help getting assets in, feel free to PM me! And marketplace creators, if you read this, please make sure to include the unit size of your assets! It really helps so much!