What size should I use for images?

If your question is in regards to the featured image size on your blog, please read this article >

Otherwise: 

• Full-column width images on your Jottful website are 708 pixels wide. 
• To make sure your image is displayed crisply on high-resolution displays, we recommend you upload an image that's twice that size: 1416 pixels wide. Uploading an even larger image is fine, too: our system will automatically shrink it.   
• If you upload a smaller image, it will be "upscaled" to fit the space but will look blurry, depending on how small it is and the device being used.    
• To make sure your website loads quickly, we recommend using JPEG images. (And in case you're wondering, the number of dots per inch — or dpi — is irrelevant. Anything's fine.)