Can you paste the full text of the error message? That often gives a more specific clue to what went wrong, and what the problem is...
You might have not saved the photo in the right sport or you have not saved the file your working on yet. You need both files to be saved in the same area so NetLogo can find the picture if that makes sense. If your file is already saved try resaving the folder where you saved the file you are working on. Else save the file you are working on where you saved the photo. I hope that makes sense/ works!
Agreed. Maybe not the right location. Maybe not the right file extension (.jpg or .png)
I agree with Renee. Also make sure that the image type is either of JPG, GIF, PNG, or BMP.