Hatch Theme Attachment Page Gallery

Hello, I am using the hatch theme as a portfolio site. I have it set up in the native wp gallery so when you click the thumbnail the image opens into the attachment page, but it keeps the thumbnails under the image.

I’m having two issues. The biggest one is that not all of the thumbnails show up underneath the attachment page image. I am not sure how it is sorting which thumbnails show and which don’t- it’s never a set number either. I thought maybe it was by date of upload.

To see what I mean- try clicking on one of the image in the top row. And then try clicking on one towards the end. It loads completely different thumbnails from the media library that arn’t even in that gallery…

https://micheleboyer.com/sculptures/

My second issue is that I can’t figure out how to set a maximum image size for the attachment image. I have tried the imsanity plugin, bulk image resizer, and a few others, but none are changing the image size on the attachment page.