To publish a Tumblr photo set in Kapost:
Select Content from the settings menu on the left navigation bar.
On that page, enable Galleries, and select Tumblr as your destination for gallery settings. Click 'Save Changes'
On your HTML Tumblr content assets, you will now see a section called Galleries.
Upload your photos there and publish your content.
Notes: Even though it looks like you can add a caption/title to each image, the Tumblr API only supports captions for the first image. To include a caption, you can either include a caption in the content text area or create a custom field with the field name kapost_tumblr_photo_caption to capture the caption. Do not use the Caption and Title boxes on the Gallery itself as the Tumblr API will ignore them.