Board Thread:Support Requests - Getting Technical/@comment-3581054-20161110113608/@comment-24473195-20161110131154

The default setting is that it fits to page, so if it only lists 3 it is because the images are too big to fit more without tighly packing them:

Number of columns columns=[number of columns] or perrow=[number of columns] Fit to page*

I suppose it might be possible using CSS, but haven't looked into it. The fact is that there are more things to consider aside from just the image width. The caption of the image can't possibly be added properly if one deliberately changes how it shows up because of its length. Also, it uses 700px for the whole width (at least on my device) so at best one could only fit 5 images as each uses up 120px, with very limited spacing. Using the preview screen, only 3 images fit on that article without a scrollbar even when those settings are changed to 5 images per row.

That being said, there might be a server side setting that can be added to default to more images, but you'd need to contact staff to ask if it is possible or try doing it using javascript / css.

P.S. I think most of the spacing is indeed reserved for the caption, about 185 pixels, and some of the captions on that page need that space to show up properly without spanning multiple lines.