Can I use a group of objects as a frame for pictures?

Question

I want to create a frame for photos that looks like the WhatsApp speech bubbles. There you have a rectangle with rounded corners and a little triagle at the left side. If I create a rectangle and a triangle and merge them with the pathfinder, I can insert a picture into this frame so that the picture has rounded corners and the little triangle at the left side. But if I want to insert another photo with another aspect ratio and scale the frame to the new aspect ratio, the little triangle will also be resized. And I want to avoid this. So it would be great to group the rectangle and the triangle and only resize the rectangle to adjust the size of the frame to the size of the second photo and use this group as a frame.
At the moment I have to choose a size for the photo and adjust the rectangle and triangle and merge them with the pathfinder, but I cannot resize the image later, else the little triangle would also be resized.
Is there any possibility to do this? Other solutions would also be great, the main thing is that I can adjust the frame without scaling the little triangle...

Answer 1

I think you don't know exactly what I mean. Here is an example image. I want the little triangle to be a part of the frame so it also contains a part of the picture. The selected object in the photo is the inserted image. And as you can see, the triangle does contain a part of the image. If I only insert the picture into the rectangle, the triangle is empty and it looks a bit stange. And if I resize this object, the triangle will also be resized...And my aim is to just adjust the rectangle and nothing more...