What kind of lag? Different types might have different causes. Size of art library is almost certainly unrelated to lag. Your art library is not loaded into browser memory. You could possibly run into memory issues while actively browsing your art library, but even that is not very likely. Some things to check: If you suspect it is dynamic lighting related Make sure your browser is set to use Hardware Acceleration if using dynamic lighting Turn vision off on NPCs Reduce complexity of DL blockers: avoid using the freehand tool; it generates far too many points. Other possibilities: Turn off autofill and autocomplete on your browser. This can cause lag in inputting values. Reduce size of maps, mostly reduce the number of grid squares Reduce number of tokens on map and number of art assets used to build a map. The more discrete objects that must be tracked, the more work Roll20 has to do. If you can assemble a map offline in a graphics editor and upload it in one or two pieces, it will likely be more performant than a map made of dozens of tiles and images. Offload the work of audio or video to discord. I prefer to use Roll20 for video and discord for audio. This is low likelihood, but it's something to try.