Sorry no one answered your question back in 2017! I'll provide my workaround now in case someone else might find it useful. Also, I'd welcome other suggestions if there is a better solution.
I don't know of a way to upload them directly to the pencil code server. I have students upload them to google photos, and then access them via a link to those files (i.e., call wear with a string argument containing the full URL of the file, which you can find by right-clicking (PC) or two-finger clicking (mac) on the google photos image. Once they do that, they can use the saveimg function to save a local copy, which they can then reference subsequently. (Type saveimg at the console to see the usage.) The local copy is useful because the link to the google photos file will only work for that account holder, when he/she is logged in.
(Note that you could also load files to sites such as imgur.com
, which can create a permanent link and make the process easier. However, my school blocks that site and others like it for kids so it is not an option for me.)
Note that files are limited to 1mb on the Pencil Code server, so you can only save relatively small images.