Get an account and use it. Probably not for Film, but for everything else.
Then plug a camera/phone+camera into your Macbook Air and say “yes” to automatic uploads of photos. Dropbox will add 3 GB of photos to your 2 GB free account if you eventually add that many photos. (You can delete the photos later, disallow automatic uploading of photos, and still get to keep the 3 GB, for a functioning total of 5.)