When photographing dogs, a good photo leash is essential in your toolkit. I use my handmade photo leashes as standard on every shoot. Because they are thinner than regular lines, you can easily get them removed in Photoshop. This makes it look like the dog is loose.
 
From my own experience, I designed a photo leash with a double stop. This prevents the leash from loosening, keeping it secure and comfortable at all times. The leash is suitable for both small and large dogs and available in two thicknesses: 4 mm and 5 mm.
 
The photo leashes are available in black and light brown. 
Please note that because the leashes are relatively thin, they can be painful on your hands with a strong dog. So when a dog pulls too hard, this is something you can take into account.