Open the jpeg or PSD file in Photoshop and select the Slice Tool

Divide the sections based on content. No more than one clickable link or button can be in a single section. You can use the Slice Select tool to adjust or delete slices.

Do not create slices for live text, such as Subject Line and disclosures (gray numbered boxes indicate auto-generated slices; these will not be exported)

Go to File > Export > Save for Web (Legacy)

Select JPEG Very High quality (Quality: 80) and click Save

Choose the name the images slices will save as. They will automatically be numbered and saved into a folder called “images.” In the Slices dropdown menu, select “All User Slices.”

If you select “All Slices,” you will have to manually delete any slices containing live text.