Compositing/croping question

[FlipTopBin]

Using version 2.8 still but can upgrade if it will make things easier:

I am trying to add though bubbles to pictures and have found a nice bubble png I can put on top of my pictures and that works fine.



The next step is to insert another picture into the bubble, so I drop the thought image on top of the bubble to create a new layer:



Now I need to crop the thought image to the central area of the bubble image. I can use the color select tool on the bubble layer to get the cropping area but I cannot work out how to crop the thought layer using that selection to trim the legs in this image to the size of the bubble. As soon as I switch to the thought layer the selection area changes.

Any help appreciated.

[rich2005]

Not sure what you are doing ie. As soon as I switch to the thought layer the selection area changes Color Select not the best tool for this.

You have your background image - the bubble
You add a layer on top - something with a transparent background.

Make the selection using the background layer, fuzzy select usually works.
example: https://i.imgur.com/SNHmZsh.jpg

Switch to the layer you want to trim.
Invert the selection, Select -> Invert then cut the selection Edit -> Cut
example: https://i.imgur.com/94jy9EU.jpg

[FlipTopBin]

Thats exactly what I wanted to do. Thanks!