When to use image resize operators The image resize operators are useful when you want to ensure that an image is displayed in a suitable size. Generally this will be used to get a cropped thumbnail of an image, or to create a responsive image for a mobile-friendly template. Syntax Resize a single image url resizeImage(imageUrl, newSize, optionalRatio) The resizeImage operator takes 3 parameters: imageUrl - The original URL of the resizable image. newSize - The new width of the image (optional) ratio - The integer ratio of width to height for the resized image, e.g. “1:1” or “4:3” Notes If the imageUrl parameter is not a resizable image, the resizeImage function will return the original imageUrl. The ratio must be integer numbers. If the ratio is provided, the image will be cropped to those exact dimensions. Example <img expr:src=’resizeImage(data:post.firstImageUrl, 300)’ /> 'resize' Operator - Google Product Forums