Images are cropped to 240×180, if you are using sizes/ratios other than these you may run into problems.
- You can choose a different version by going to Directories –> [Your Directory] –> Content Types –> Category –> Manage Displays –> (Name of Display to Edit). Edit the Photos display element there and select a different image size.
- In my (Dave) opinion this is less than ideal and making full use of WP’s responsive images functionality integrated into core in 4.4 should make it possible to avoid this issue entirely.
- There are also some restrictions on the responsiveness of images caused by Directories Pro’s use of the CSS property background-image for displaying some listing images instead of the HTML img tag. I (Dave) think using img is a better route than background-image for this usage case. See StackOverflow for further discussion of this topic.