Saving as image only once?

I have just started in Blender, and I am keen on experimenting with Blender results in Photoshop. So I wanted to save an image. I am pretty new to Blender, so I googled and experimented and as it turned out, I rendered my final image and did some other things on it way past when it said “render result”. Not is says “object mode” and I can’t render it anymore to say “render result” so I can save it as an image. Is it possible that you can only save the file as image only immediately after rendering it?

Also, I tried to open it in my UV editor- nothing shows up in there, totally blank. Do you have any idea what’s the problem?
I don’t have a strong graphics card so I’m using Blender 2.76. Please help, much obliged.

Render properties with the render buttons have a dropdown menu for displaying the rendered image. “Image editor” is the default, which switches the largest editor to the image editor to display the render.

Single frame won’t save automatically without setting that up separately. It keeps the image in memory until it gets overwritten with another render or removed. While in memory, it can be accessed from the UV/image editor, selecting it from the image list if needed. If it’s not there, you haven’t rendered yet or have removed it since you opened Blender.

2.76. As long it’s from it’s fine I suppose. If it’s from anywhere else, you’re wasting everyone’s time.