So depending on how you created the Image Column, as it has changed, you can pull back one of the different sized Thumbnails instead of pulling back the entire full image.
But it depends completely on when and how you created the column as it changed and became super annoying....
But in this case you have to use the Send HTTP Request to SharePoint to grab the thumbmail you want. That would shrink it down a lot.
You could split it into chunks (the larger image) yes, you could also have SQL Server itself grab the data using a Sproc, you could also save the file in a library, and pass the Url to SQL and have SQL grab it, there are also PCF Controls out there that can do this, or you can build one.
Lol I made the mistake in my inventory app not to remember to fix my Column so that it actually gives me a url to the image... i had to redo the whole stinking list as the images were near impossible to get them out. It doesn't seem you have that issue, so go with grabbing the thumbnail size versions.
Or if you really need the whole thing, you are going to need something like Encodian or a PCF control (pre sharepoint) or having SQL grab the data.
Just some additional thoughts.,
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Thank you!
Sincerely, Michael Gernaey