How to Edit Image Size in HTML on Tumblr. If your blog images are too large, users may have to scroll to see them. Make the images too small, and blog visitors might not notice them.

The image size can be changed using simple methods. We show you the best ways and tools for lossless compression.

Double-click the image file you'd like to include in your post. The File Upload window closes and your image appears in the editing box. Click the "HTML" button and review the HTML code that appears.

FixPicture is both an HTML and Flash-based tool for quick image manipulation when all you've got is a web browser and a picture in need of some work.