You will want to resize your images for the web. Standard web image sizes are between 800px and 1000px. Your Photocrati theme is designed to be 960px wide. So for images with a standard 2X3 aspect ratio, you should consider sizing your images to be 800px X 533px, 960px X 640px, or 1000px X 667px.
Why You Should Not Upload High Resolution Images
Some photographers think that if they upload high resolution images, their images will display more sharply or with better color rendition. However, it’s important to understand that no matter how large your image files are, their DISPLAY is limited by the resolution of the computer monitor. Say a typical computer monitor has a resolution of 1200px wide by 800px tall. By definition, you simply cannot display an image larger than this on the monitor. If you upload a high resolution image, say 3000px by 2000px, your monitor will still display it at a maximum of 1200X800. So there is simply no reason to upload a large file size for the internet. (Note: 24 and 27-inch Macs have a standard resolution of 1900X1200 and 2560×1440, so high resolution images will be resized by your monitor even with those massive monitors).
Built-in Photocrati Option: Display Full Size vs Automatic Resizing of Images
With Photocrati Galleries, you have two options for image display. Go to Theme Options > Gallery Settings. The first setting concerns image resolution. If you set this to Full Resolution, Photocrati will display your images exactly as they are uploaded – no resizing. If you set this to Resized Images, Photocrati will display an automatically resized (generally smaller) version of the image that is optimized for speed. The resized images are reduced to a maximum of 960px wide. Both the full size and resized images are stored with your theme files, so you can switch back and forth whenever you want.
Please note that if you choose to resize images, the images go through a compression process that may have slight affects on image sharpness and color rendition.