In google apps Script you can insert an image into Google Spreadsheets using the insertImage
function (https://developers.google.com/apps-script/reference/spreadsheet/sheet#insertimageblob-column-row).
But I'm not using appscript. I'm using the Google Sheets API (https://developers.google.com/sheets/api/reference/rest/v4/spreadsheets) and I can't seem to find a way to do this. Is there any possible implementation?
The V4 API doesn't have the ability to insert an image blob like Apps Script does (where the image is an overlay on the sheet, not associated with any cell). You may be able to workaround this using the =IMAGE function. We know of the gap in functionality and are looking into adding support for image blobs.