can't upload maps, please help

I'm trying to set up my dnd campaign but for some reason, half of my PNG files won't upload.  

How big are the files? JPG with 50% compression are usually a lot smaller, and so are preferred for roll20 (less data to send to each of your players).

2-4mb

The maximum file size is 5 mb, but smaller map file size is preferred. Why not see if JPG at 50% compression create much smaller files?

Uploading opaque images as jpg is the formal advice. Alas since a certain date last year, roll20 converts all jpg's to png before uploading.  As long as that bug is not solved, you are better off uploading PNGs, as you at least know which files are large. jpg's with 50% compression might explode 10 fold in size. If you want to check whether the bug applies to you? Drop an image on the page, wait for it to upload, select the image, press Z, right click and save the image (will be named original.jpg). Compare this file with the file you uploaded... 

I don't know why this is either (have investigated), but I believe that the original upload size is used for calculation of Art Library usage still. At least the original size is maintained in the metadata of the library.

Come to think about it. Are you uploading the images one by one or do you drop in a bunch at the same time? @keith With a pro account my concern is not with the billed image size but with the actual size. Amazon s3  supports at least 3,500 requests per second to add data.   If that are concurrent requests, you do not need that many 15 minute ‘8MB Jpg’s exploding to 50MB‘ Uploads to clog up the system.

No worries, Martin. I added that last bit for the benefit of others following along, in case of general concern. Requests to reduce used storage space are pretty common. Thanks for reminding me of the conversion issue. I'm trying to find out what I can.

apparently 2 of them where 5mb, 6mb and two more where 7mb, 8mb. i didn't know the max size was 5mb and sorry for the late reply work sucks