Formatting the size, shape, and file type of images are important for an app's performance. When we have very large image sizes, often times it can slow performance on the front-end. Additionally, the image file type can affect performance on the front-end. For general use, we recommend using .jpg file types for images. This is because .jpg is a smaller file type making it easier for the front-end to load. However, if you require transparency capabilities or very high image quality, then you might want to consider .png.