There are a number of reasons that an image cannot be uploaded to Etsy:

• images must be at least 1000 pixel wide
• the image file is no higher than 300k in file size otherwise the upload may time out

If the image meet the above criteria the try enabling the “Automatically enlarge images” in the Etsy listing setting:

• navigate to ‘Setup > Listing Setings’
• edit the Etsy listing setting
• enable “Automatically enlarge image” in the images tab and save change