Great Question! Yes.

It is best to edit photos prior to upload, since resizing them in blog posts or pages does not change the file size. All images, however, do get resized upon upload to the Media Library.

Default image sizes for specific user blogs can be configured in your Dashboard -> Settings -> Media

Set the maximum width and height for uploaded images that best correspond to your selected blog theme. Setting a size that fits your blog post width, will prevent the need for resizing photos after they are added to posts or pages.

When uploading images to be used in the header image or eleswhere (e.g.; full-width pages), set larger image dimensions for the Large size to avoid pixelation of enlarged images.

Image size settings will only affect future uploads, not existing image files in the Media Library.

Once image sizes have been configured, all future uploads will be automatically resized to the set dimensions.

When adding images to blog posts or pages, be sure to select the desired size to prevent pixelation (if photos are enlarged in the post), or unnecessary bandwidth use (and slower page load times) when larger images are scaled down.

FYI: All images uploaded to all Tripawds blogs are automatically resized to a maximum of 1024 pixels wide, and optimized to limit file size.