Technically, the image field in the Plus Editor support the file types BMP, GIF, JPG, PNG and SVG. We would always advise you not to use BMP files because they are not compressed and larger in file size, which makes it slow for the browser to load.These would be the best options for file types:GIF: For animated images, because they can consist of multiple frames. It's not suitable for photos, because it only support 256 different files in one image. (JPG support over 16 million)JPG: The way that JPG files are compressed is especially suitable for photos, but not for illustrations. Data is lost when saving a file as JPG, which can be noticeable if an illustration has sharp lines and plain coloured areas. "Messy" pixels might appear around the lines and areas.PNG: The way that PNG files are compressed is especially suitable for illustrations that have sharp lines and plain coloured areas, but not for photos. Data is not lost when saving as PNG, but it will be saved in a way to take up less space. If you save photos as PNG, the files will become quite large (because nearly every pixel has a different colour) and it will be slow for the browser to load.SVG: These are vector images that don't have specific image size. These files contain information about the positions of lines, shapes and colours. This is a small file format that is suitable for illustrations and can be displayed in good quality in any size. You can only create this kind of file in programs like Adobe Illustrator.