There were two missions that had San Juan in their name. San Juan Bautista and San Juan Capistrano. Look at the map on our website so you can see which one you will be visiting.
We have several great images of both missions on our website under the key facts of each mission.
You can also find lots of pictures using a web search engine like Google, just type in the name of the mission and search IMAGES. There were over ten pages of images that appeared when I did this the other day for San Juan Bautista.