Image URLs not showing up in Google Sheets

I’m having trouble with something I thought would be extremely simple. I’m creating an image archive on Google Sheets, and in order to insert images into their spreadsheet cells, the images need to come from a URL address, not my laptop. To do this, I created a WordPress page with a gallery and uploaded my images to it, and now they all have a custom url I can source from.

So, I’ve got a working gallery page with all the images, the correct formulas for embedding them via url into Google Sheets, but the spreadsheet with the url formulas is totally blank. It worked a few days ago at first, but now nothing shows up, or, when I refresh the page and scroll up and down, some of the images show up and some don’t, with no rhyme or reason to my eye.

Is there something tricky or unique about wordpress image urls that I don’t know about? I tried changing the link setting of the gallery back and forth from “image file” to “attachment page” and it made no difference. All of my images are web-optimized at under 1MB and it’s a private page.

There are 230 images in the gallery, and I’ve tried uploading about 80 of them to google sheets (before things stopped working). Is it my outdated 3.3.1 version? A size limit? A google error? Any help would be deeply appreciated.