Best way to create decorative borders for raw image

You can find decorative borders including free borders on Adobe Stock  Stock photos, royalty-free images, graphics, vectors & videos | Adobe Stock

In photoshop give Filter>Render>Picture Frame a try.

For some inspiration examples have a look at this link (rather 'old')

http://projectwoman.com/articles/47PhotoshopFrames.html#.YsIi0oRBy8E

Some questions:

-Are you an artist?

-Can you show an example of the images in this project?

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I'm not sure what you mean by "line-bending tool," but there are various ways of creating curved lines in Photoshop. I think you'd want to draw them/make them yourself rather than bending an exisitng line, which would create artifacts. As to the decorative borders, again there are various ways of doing it. Here are some that I've made and use in my work. Is this the kind of thing you mean? Would the borders be drawn/painted borders on photographs? Or on illustrations?