Here’s the procedure I’m using without issue, it’s a little roundabout but avoids the issues you’re having.
Step 1: Load your record placeholder and store the photo into a photo array. It’s easiest to create an array within the if/then logic screen so you know the array type is correct. It should be a Photo URL Array
Step 2: Then you need to use TOTEXT and move the photo from the photo array to your string array that you want to use to construct your email body
Step 3: Finally you’ll use Arrays → Join to String to concatenate that string array into a single string that can be emailed
Below you can see a sample of an email I created, along with some other information from the app that I pushed onto the string array along with new line characters before the join to string operation.