You can sit in a park or stare at a photo, trying to word a description. The image is there but you are finicky about how to word the scene. "A picture is worth a thousand words," is the common phrase. A thousand words can take ages to write or no time at all. It all depends on you.
I can see you have a little of a perfection complex. Don't try to deny it. When you see an image before you, you want to do it justice in words. You study it and squeeze your brain cells, trying to figure out just what to write. Meanwhile, the only ink on the page before you is the tap-tap-tapping of the pen. Dot-dot-dot does not a fascinating tale make.
What to do about this dilemma? I have a solution.
When you are trying to write from a visual stimulus, your brain divides the task into two things: pictures and words, oil and water. They seem so different and refuse to mix. You are forced to create some kind of alchemical equation to turn pictures into words. Your result is dot-dot-dot and a headache.
Remember what I told you about your eyes being a camera? Well, I may not be six anymore but I still believe it's true. You can use your visual senses, memory and imagination to solve this conundrum.
1. Look at the scene you want to describe.
2. Close your eyes.
3. Allow that picture to stay there for as long as you can hold it. Savour it.
4. When the visual of it disappears, remember it.
5. Imagine it as something moving, not a still image.
6. Open your eyes at the page in front of you, not the image you were looking at.
7. Write without looking at anything but the page. Do not look back at the scene/image you are writing about.
Perfection is not your friend. Imagination is the sword which writers wield. Sure, it can be a little unruly at first but you'll master it before long.
Just remember, a writer's camera is never forgotten.