Once you select the picture to assign to your new entry you will be returned to the main data screen and will see that a thumbnail version of the image is present below the 'Tap to enter Form Data' button.
Also, please note that the 'Photo' button text has changed (in a similar fashion to the Assign GPS button text) to indicate that you have completed this part of the data entry for this new entry. You may also tap the photo button to change the photo if you are not happy with the image you have taken.