When we want to insert an image via URL, Quill’s delta (content) will look like this:
{"ops":[{"insert":"First Line\n\nThird Line\n\n\n"},{"insert":{"image":"https://a11cc7327bf2e336a7d1e3bfe2c366e8.cdn.bubble.io/f1692798108294x902168513112584700/Plotly%20Logo.png?_gl=1*213awx*_gcl_au*NzA1ODk1ODQuMTcwNzU3NTE3Ng..*_ga*MTc1MTIzOTUzNS4xNzA3NTc1MTc2*_ga_BFPVR2DEE2*MTcwOTgyNzQwOS4xOS4xLjE3MDk4Mjc2ODEuNi4wLjA."}},{"insert":"\n"}]}
So, you can insert the image’s URL by making changes in the delta in the database with the same format as above.
Note that you shouldn’t save it as text because in that case the image will be saved as base64.
Sample page with edit access:
Quill Content (bubbleapps.io)