So you want to find the center of that image for whatever reason. No need to measure and make calculations. Instead, try this easy way:
- Select the “Pick tool” (Keyboard shortcut V)
- Then look at the toolbar (yes, it is there, what, you never looked at it with the pick tool?)
- Put a check mark in the box next to “Show Transform Controls”
- If the image has layers, any selected layer will show the transform points with the center of the image also marked. If the image is flattened and there is only the “Background” press Ctrl-A to select all. The transform controls will immediately appear.
- Drag a guideline from the vertical and horizontal rulers. As you bring them close enough to the center point they will snap to the center point. After you place a vertical and a horizontal guide they will be visible even after selecting a different tool.
- If the guides do not snap, turn this on from the menu “View/Snap to/Guides”