I have a high resolution image (TIFF) that I need to fit in a 320 x 440 px asset for the web (preferably JPEG). The high resolution image is usually a photograph and can sometimes have a logo burned in as well. This asset must also be under 300 kb. How do I keep the file size small enough while also maintaining the highest quality possible (for retina)?
You should be able to save an image that is 320x440 at max settings and easily get under 300kb if you save as a jpg. If this is your own website, I would save at a lower quality so my web pages load faster.
If you want to save for a retina screen, then you have to export at multiple sizes. So if your image needs to be 320x440, then your 2x image will be 640x880.
See relevant question: