Aspect ratio for images

## Is your feature request related to a problem?
Images for case studies currently don't have a set aspect ratio

## Describe the solution you'd like
For images in the body of the case study, aspect ratio can be 3:2. Minimum size on large screens would be 1170x780.
For images in the header of the case study, aspect ratio can be 3:2. Minimum size on large screens would be 1740x1162.