Post Field—Image upload isn't working

The Post Image field uploads the image to your Media Library and attaches the image to the Post that is created. The image isn't going to automatically show up in your post. For one we wouldn't know where it should be displayed or how it should be displayed.

Just like if you go to your Media Library and upload an image, or go to Add New Post and click on the upload image icon and upload an image, they don't automatically get added into the Post Body of a post unless you insert it into the Post Body.

If you want the image to be included in the post body then you need to edit the Post Body field on your form, turn on the Content Template option and then in the Content Template configure your post. Whatever appears in your Content Template is what will be used as the content of the post that is created, including any field merge tags you include. Merge tags are replaced by the actual fields value when the form is processed and the post is created.

You can use the "Insert form field" drop down above the Content Template to insert form field merge tags. So using this functionality you can insert the merge tag for your Post Image field, including selecting which size from the Media Library sizes.

Just remember that the Content Template overrides the Post Body field itself and whatever you configure in the Content Template is what will be used to create the content of the Post.

The Content Template supports shortcodes so you can also include the [gallery] shortcode in the Content Template if rather than manually inserting a Post Image field merge tag you want to show a gallery of all the images that were uploaded with that Post.