I attempted to do this a couple months ago and found no easy/built in way to do it in Tableau. I could not find a way to dynamically load an image URL in a dashboard--you'd think the option would be there, particularly since other features of Tableau come close to this type of functionality.
I did find one legitimate workaround, using Shapes and usernames, and another option for dynamic images using background images but the building this functionality into Tableau would be nice.
Please vote up the Idea: http://community.tableau.com/ideas/1101
The Shapes workaround was described as shown below, by Dimitri Blyumin
Here are the steps:
- Add custom shapes folder with your school logos, as described here: http://onlinehelp.tableausoftware.com/v6.0/online/Output/wwhelp/wwhimpl/common/html/wwhelp.htm?context=Tableau_Online_Help&file=Tableau%20Online%20Help-15-23.html
- Create a text or Excel file with the list of your users (usernames, as per their logins), and connect to it as a secondary data source.
- Create a sheet with just usernames on rows (or columns) shelf, and nothing else.
- Switch to Shape graph type, i.e. each user gets their own shape.
- Edit shapes, select your custom logo shapes and assign relevant logos to respective users.
- Hide header and other elements of the sheet, leaving just logos. Don't worry about multiple logos showing and any scrollbars at this stage. Resize the shape to the desired size using Marks card size control.
- Set up user filter as per part one above for this data source, allocating server users to their respective user names in your data source.
- Place your logo sheet on the dashboard with your other graphs etc., resize as required.
- Publish workbook to server.