I use InDesign for wedding album creation. I make a bunch of spread templates that I choose from to make the album.
So I can easily see the number of photos on a page and where to drop the photos in the spread, I make the empty frames with a bright green fill color. I have no stroke selected on the frame, and I have the frame set to auto-fit/fill-proportionately.
In InDesign and when I export the spreads as JPEG's, I can see a small, probably 1 pixel line across the top and bottom of the photo when I view at 100%.
I can fix this by selecting the frames after designing the album and changing the frame fill to being blank...but this is tedious and I don't know why it is even showing.
Anyone have any ideas on how to help? If you want me to send over a InDesign file to look at it...I can do this.
If the forum allows links, here is a crop showing the green line on the bottom of the photo. You can clearly see it on the bottom right of the frame where there is white in the photo.
Can you export as pdf and see if you have the same problem? I don't know if pdfs fit into your workflow though.
Not so simple solution:
Duplicate the green boxes onto a new layer and set the fill to none. (Make sure this new layer is above the green boxes layer.) Then make the layer with the green boxes non-printing by double clicking on the layer name and deselecting the check box "Print Layer"
Depending on how many spreads and templates that you have this could take a bit of time. Sorry.