How to Do Photo Sets on Tumblrby Alan Sembera
Tumblr's Photoset feature enables you to create and publish your own photo montage without using any additional software or scripts. You can add up to 10 photos and arrange them in any order you like. You can leave them in a single column or place up to three of them side-by-side and let Tumblr automatically reduce the display size to fit the column width. You can even use animated GIFs instead of photos to add motion to your arrangement.
Click the "Photo" posting option for your blog on the Tumblr dashboard.
Add up to 10 photos in any order to the gray photo area on the page. Drag and drop a picture from your desktop or file browser, or click the camera icon to select an image file from your computer. You also can click "URL," and then paste in one URL for an online image -- although to add subsequent online images, you must first save them to your computer.
Click a photo and drag it to the desired location in your photo arrangement. To put a photo next to another, drag it to either side of the other photo until you see a blue line, and then release the mouse button. Put up to three photos in the same row; Tumblr resizes them automatically.
Hover your mouse over a photo and click the bubble icon if you want to add a caption to a photo. Enter the caption, and then click "Set Caption." This caption only appears if someone clicks on the photo in your blog.
Enter a caption in the Caption box at the bottom of the screen if you want to include text that will appear below the photos on your blog.
Click "Post" to publish the photo set.