unwrapping:

Tumblr Dashboard Image Sizes:

• Photo post: 500 by 750 pixels for dashboard view; 1280 by 1920 pixels for high-res version (except for superwide panoramas).
• Photoset: 500-pixel width for one image in a photoset row. 245-pixel width for two images in a photoset row. 160-pixel width for three images in a photoset row. Gutters are 10 pixels.
• Audio Post: 169 by 169 pixels for album art.
• Link Post: 130 by 130 pixels for the thumbnail image grabbed by Tumblr from web link (if available).
• Text Post: 125-pixel width for images added to a text post, which expand when clicked.
• Avatar: 64-by-64-pixel icon next to posts.