Intermittant - Not able to send photos via email

I would like to send photos via email from my iphone 6. I can do this sometimes, I was able to do it yesterday. I am at home, using wifi. I take a photo, it is usually to do with a picture I am painting, I wish to email it to myself, so I can save the picture on my laptop. My laptop isn't an apple. As I say this only works intermittantly. Before I had an iphone, I never had difficulty with this process. I wonder if it has anything to do with how long the picture has been on my phone, is it to do with the icloud? Is it to do with the number of pictures I have stored.