Insert a photo into a photo layer of a collage file

I really appreciated your time in sharing this way to answer my question.

There is no standard document formats for photoshop template PSD template file.  The are many different template designs.   Since its not your PSD template design. Its one you purchased it would not be popper for you to post  You need to provide better information about the  PSD layers structure.  Place is a very strange Photoshop feature and IMO is not the  Photoshop features to use to populate images into a psd template.   Place will resize and degrade image files that are place into a  document that resolution does not match the image file Print Resolution setting.   

Photoshop's new Frame tool has issues because it uses Photoshop Place feature and the Adobe developers that implemented the Frame tool did not understand how place works.  The frame tools has image resizing issues. So I would not recommend considering adding Adobe Frame layers in Photoshop Template PSD files.

The word 'Place' suggests that you do exactly that.

Select one of the collage layers, and go File > Place Embedded and select the desired image.

Before you start, open Preferences > General and make sure your settings are as per the two I have highlighted in green

This will ensure that the Placed image will have a transform bounding box and handles for you to size, and ensure it is placed as a Smart Object so you can resize again, as often as you need, without loss of image quality.

You have not said what Photoshop version you are using, but if it is CC and up to date, consider using The Frame Tool which is ideal for creating collages

I'm not sure about how is your document, but here are three things you can try:

1. Double click on the layer thumbnail where it says place your image here. If it was an smart object it will open a new document and you can place your image there.

2. Convert the place to a smart object, right click on the layer, the select convert to smart object. If you make this, than you can just follow the step one after that.

3. You can clip your image into the form. Put your picture in the top of the shape layer, then press Ctrl + alt + G.

Hope some of these can help you. 🙂 Or, try to post a Pic of your document.