Managing Virtual Maps

Jeff Montgomery -

Making it work for the Virtual Table Top

If you want to list your titles in our VTT category:

Please do your research and optimize your files for customers to be able to easily use them in the most popular VTT platforms.

Some publishers offer 15MB jpg files advertised for use with VTT when the most popular VTT service, Roll20, has a file size limit of 10MB.

Some publishers offer VTT at dpi of 100 or 150 instead of 72.

If your VTT product is not ready to drop into Roll20 and be immediately usable then you should reformat it so that it is. If the customer has to use Gimp to crop and compress your file to get it to work, you have a customer who is not excited about buying your other map products.

Roll20 accounts are free, open one and make sure your files work there. Your customers will become repeat customers.


You can read Roll20’s map image guidelines here:


And Fantasy Grounds here:


To ZIP or Not to ZIP

Zipping image files typically does not add extra compression to them, so there is no reason to zip for file size reasons. The number of files associated to a product is the only determinant on whether to zip the files or not.

If your product would have over 10 individual files associated to it, then you should definitely zip the files.

Some publishers have products that include over 100 different files. This becomes a nightmare for customers to download after purchase. We get refund requests from customers who buy such titles soley because they have no desire to slog through downloading them all. Even those customers who slog it out are less likely to buy future titles from you.

On the other hand, some publishers have instances where they have zipped a single file. This just forces customers to download the zip, then have to unzip it only to get their single jpg file. Again, this creates work for the customer. Just offer the jpg file directly, don’t zip it.

Most often the optimum approach here is to group your map products files in sensible ways and zip the files associated. For example if you offer gridded and ungridded versions, you might zip all the gridded files together and then group the ungridded files in a second zip file.

Or if you have high resolution (printable) and low resolution (VTT) versions of a map, you might zip each of those files types separately.

Zip as needed so that your title has 4 of fewer files to download is usually best.


What resolution?

We think your map products should be offered in two formats:

  1. High resolution printable. This would be done at 300dpi and offered as a CMYK colorspace jpg file.
  2. Low resolution for VTT. This would be 72dpi with a full map version for reference (if needed) and then the map broken into sectional pieces of smaller file size for actual use on VTT.

We all want your maps to be gorgeous, but most maps could handle a small amount of jpg compression and still be just fine. As an example, I downloaded a battlemap product. The jpg file was massive at 170MB. After I opened it in my image editor, I saved it using a compression level of 99 out of 100 and the file went to 122MB. Using just 98 of 100 the file went to 101MB.

There was no discernable difference in image quality when I zoomed in on the map (down to a pixel level). Whatever your image editor, using just one degree of compression on its scale will net you a large file size reduction without sacrificing any discernable image quality reduction. 

In the era of broadband, we often think file size doesn’t really matter any longer, but it still does for several reasons.

Especially when you are offering several variants of your map, the file size reduction from a small level of compression multiplies over the variations you offer to a become a big difference in total file size. This means the customer’s download is faster after purchase. It means our bandwidth costs are reduced (map products are far and away the highest users of our file server bandwidth). And most critically for your VTT versions, small file size makes a big performance difference when players use your maps in the VTT programs.

Have more questions? Submit a request


Please sign in to leave a comment.