Customize Tumblr theme for portfolio website

I'm looking to put a very simple portfolio site up, set up as a Tumblr blog. I have a theme selected but unfortunately the person who created it does not have time to edit it. The current theme is very close to what I want, but the main difference is that I would like to add a clean, large photo slider that allows me to show multiple images for each project. See attached for two images I mocked up in Photoshop. The initial "home" page would show a grid of images - each image would show a different project. Clicking on the image would take you to that "project" page (or "blog post")… which is where I would like to add a slider for multiple photos, and also a caption. All the text in red in the mockups are intended to be notes to you, and obviously not part of the design. I have no preference whether or not you want to edit the existing theme or create a new one. The theme that I would like to use as a base is the following: [login to view URL]