one way to do it is to create a custom layout in the PhotoSmash Admin --> Layouts Editor page to go with your custom form.
As you're building your layout in the PhotoSmash Admin --> Layouts Editor page you can pick and choose what fields you want to include by adding their [short tag]. There are several default options and any custom fields you create in the PhotoSmash Admin --> Custom Fields page will be automatically added to the list. Just pick and choose which ones you want to include--add a little html/css formatting and then create a photosmash shortcode to put into your post. It will look something like
[photosmash form='CustomFormName' layout='CustomLayoutName'].
Using this method your layout will only display the information you've listed it to display.
If you want to collect data without displaying any of it on the blog/reader side you could use a shortcode in your post similar to
[photosmash form='CustomFormName' no_gallery='true']