How to check if a uiimage is blank? (empty, transparent)

Question

which is the best way to check whether a UIImage is blank?
I have this painting editor which returns a UIImage; I don\'t want to save this imag

Answer 1

Something along these lines:

1. Create a 1 px square CGContext
2. Draw the image so it fills the context
3. Test the one pixel of the context to see if it contains any data. If it's completely transparent, consider the picture blank

Others may be able to add more details to this answer.