How do I check if my file resolution is good enough?

It's not complicated ! You can check the image dimensions (in pixels) and derive the resolution from them:

• On Mac (macOS): Select the file and press CMD + I to display the pixel dimensions.
• On Windows: Right-click on the file → Properties > Details to display the pixel dimensions.

👉 Then simply convert: (number of pixels ÷ 300 dpi) × 2.54 = image size in cm