I wish more people would start with pen an paper when problem solving!
A while ago I added TIFF as a format to Discourse that can be uploaded so that the hand drawn images could be scanned then uploaded e.g. in this post is PostScript Number and Name object Syntax Diagram.tif
For others: I am not encouraging users to start uploading TIFF images as we have storage constraints to contend with at present but for certain cases having the image outweighs using the storage space; when we move to self-hosing the storage space increases greatly. Also remember that when creating a TIFF image, options are usually available to create a black and white image which greatly reduces the byte size of the file and judicial use of other options when scanning will also reduce the file size.
If the image is useful we could always convert it to the DOT language and use GraphViz which is magnitudes of size smaller.
Donald Knuth (ref) and Edsger Wybe Dijkstra (ref) often scanned their notes and made them available.