Optimizing blog images for SEO involves adding alt tags to the images, compressing the images, and ensuring that the images are sized correctly. When adding alt tags, it is important to include relevant keywords that are related to the content of the blog post. Additionally, compressing images can help reduce the file size of the image, which can help improve the page loading speed and SEO rankings. Finally, make sure that the images are sized correctly for the page, as images that are too large or too small can negatively affect the page's SEO rankings.