Is it less computer intensive to load and unload an image every time a new image is needed or to have all of the images loaded at once? (SDL)

I've created a small animation for a game that uses a set of images as frames, and the current image to render changes over a certain amount of time to create the animation illusion. I've done this in two different ways, and I'm wondering which one is more efficient to use.

Method 1: A single image is loaded and rendered. When a different image needs to be rendered, a function is called that unloads the current image, and loads and renders the new one.

Method 2: All of the images needed for the animation are loaded once, and then rendered as needed.

In simpler terms: Method 1 unloads the current image and loads the new one every time a different image is needed, and Method 2 keeps all the images needed loaded at once.

So basically, the question is, it better to constantly load and unload images to keep as little loaded as possible, or to have many loaded at all times and not unload/load anything during the program? Does the computer have a harder time loading and unloading images or keeping many images loaded at once?

I ran looked at the task manager while running each method. CPU usage of Method 1 (loading and unloading) fluctuated between 29% and 30%, while that of Method 2 fluctuated between 28% and 29%.

It appears that keeping all the images loaded is better according to these statistics, but the reason I don't really trust them is because the program only loads seven images.

As the game gets bigger, there could be hundreds of images loaded at once (Method 2) or an image loaded and unloaded nearly every frame (Method 1). Which method is less intensive? Thank you for your time.