Our themes use the WP_Image_Editor class and standard WordPress routines to generate featured images at the sizes specified in the theme options. These are generated once when the page is first loaded. Any subsequent page load will use the image size that was generated and is now saved in disk.
The images from a different domain can not be generated/cropped. The original image source will be used if images are from external sites.
Disabling Image Script
To disable the Image Script, go to Themify > Settings > Image Script tab. Once the image script is disabled, a dropdown will be available for you to choose which image size to use as default.
The featured image size can be selected separately in: default index layout and default single post layout (located in Themify > Settings > Default Layouts), as well as in each post editing screen (located in the Themify Custom Panel). The image sizes (Thumbnail, Medium, Large) can be set at wp-admin > Settings > Media. In other words, you can specify 250 x 250px medium size to be used in the index pages and 560 x 300px large size for single post page.
When you adjust thumbnail dimensions under WP > Settings > Media, the new sizes are not applied to the images you have previously uploaded to your site. To make the changes affect the standard image sizes Thumbnail, Medium and Large on your site, you need to install and run this plugin: Regenerate Thumbnails. The custom image sizes are regenerated on the fly when the dimension changes.