Three utilities I find helpful

1. extract images out of PDFs: https://askubuntu.com/questions/150100/extracting-embedded-images-from-a-pdf
2. Mark up images online: https://markuphero.com/try/annotate.html
3. some latex publishers require an eps instead of svg (even though there is an SVG module for Latex). https://cloudconvert.com/svg-to-eps