While cute, dogs shouldn't ride in regular backpacks or purses (such as the picture above) (thedogclinic.com)
These are similar to a regular backpack but have specialized pockets for things like diapers, wipes, changing pads and other small baby items. (momtricks.com)
It can also be used as a regular backpack when the rein is not required while the connection strap remains securely attached when being used as a harness. (littleangels.ie)