Image for Case Studies
If you are exporting a photo (from Photoshop of Gimp), you next to control the size. In Photoshop, go to File/Export/Export As/ the select what you want to do.
Please export photos as jpgs and reduce their quality. They need to be at least under 300KB, ideally they will be under 100KB. This is best for your SEO. If you are going to use a photo for the header, it needs to be at least 2500 px wide to look good on retina display. If you’re going to use a photo for a small (square) case study image, you could get away with making it 600×600.
Don’t focus too much on the Image size. You can keep them 2500 x 1900 if you want, or even 1500 x 900 for some image that will display small in the case study, but really you need to make sure the FILE SIZE is not too big. So to help keep the file size small, you may need to reduce the image size.
If Gimp is your tool, make sure you can reduce files. Also, you can use TINY png (https://tinypng.com/) if needed.