Software for Image Optimization?

I'm looking for a good software for optimize images on roll20. Actually i have about 2 GB of maps, tokens and assets on my PC, and before i will upload everything i'd like to optimize those images and reduce their size (only lossless conversion). Do you have any recommendation on good free software to use? I tried some but I get really small reduction of image size. I have Both PNG and JPG. Of course i need a software in which i can put many images at the same time.

JPG and PNG are already some of the best file sizes, and especially when you don't want to reduce the quality for JPG, you'll not really reduce the filesize, and might even increase it. PNG is a lossless compression, so again, there is not much you can do, I think you can increase the compression ratio (takes longer) but you'll not save really much that way either. Converting the PNGs into WEBP files will safe you more from what little testing I did (they were about 30% smaller than PNG on Lossless setting), but still much larger than JPG or WEBP lossy compression. As for a program, IrfanView has a batch conversion mode where you can feed as many in and it will do it for you. But why do you want to upload 2 GB of maps etc to Roll20 anyway? Just have them on a folder on your PC and upload them when needed.

Quatar said: But why do you want to upload 2 GB of maps etc to Roll20 anyway? Just have them on a folder on your PC and upload them when needed. Yeah, that's the plan, but I find deleting uploaded things a bit boring and not fast at all, so i guess that one day I will find myself out of space. Furthermore a lot of Jpg and png are actually tilesets or tokens for map (wagons, horses, woods, trees, etc) and I use them to build personalized map and I cannot delete them from the server because forests map and similar are used often in my campaign.  I'm a bit worried about the 2 GB space. I'm actually compressing every image with a lossless compression software called fileoptimizer, but it is working since 8 hours now to compress about 150-200 files and I gained roughly 10% (which is better than nothing but I was hoping for something like 30-40%). I am thinking about a lossy compression right now at about 70% rate to see if the image gets too ruined. I saw that a 50% compression will take about 90% of the file size away, but it looks quite bad, so i was thinking about a more soft compression. I maybe do a little update if I can do something decent for anyone who is interested.

Nox, I'd recommend creating your maps in Photoshop/gimp/image program of your choice and uploading the completed map as a single file. This will make your game more performant.

I agree with Scott C.  While you might not notice it if your computer is reasonably powerful, creating maps in Roll20 and dropping everything individually onto the map creates a lot of extra processing and it can cause your maps to lag when loading or scrolling around.  I've seen it myself on a map I created with something like 100 individually-placed trees on a 25 x 25 forest map. Creating the maps offline and then uploading them as a single image will make your game run better where processing and bandwidth are concerned.  When you do upload them, doing so as a 140 pixels/square jpg is more than high enough resolution for pretty much any zoom level in Roll20.

Denton W. said: I agree with Scott C.  While you might not notice it if your computer is reasonably powerful, creating maps in Roll20 and dropping everything individually onto the map creates a lot of extra processing and it can cause your maps to lag when loading or scrolling around.  I've seen it myself on a map I created with something like 100 individually-placed trees on a 25 x 25 forest map. Creating the maps offline and then uploading them as a single image will make your game run better where processing and bandwidth are concerned.  When you do upload them, doing so as a 140 pixels/square jpg is more than high enough resolution for pretty much any zoom level in Roll20. ok, Thank you very much i will use photoshop for this in future!