Images: Insert larger images into Pages and Blogs
If you find the image quality to be low or image size to be small when adding images to your Pages or Blog posts, try using the size selector when inserting images on these pages.
Choose the insert image toolbar icon:
Select an image and then use the image size drop-down:
The default is Large (480x480) which is quite small and low quality. If you choose a larger image size, you'll have a crisper image displayed:
1024x1024 might be ideal without making an impact on page load times. The largest 2048x2048 works well if your original image is that size or larger. If your original image is smaller, choose the size that best matches your original image.