You can use "PicBackMan" to sync or backup photos from Mac to Flickr account. It allows you to backup unlimited photos of all sizes and handles the complexity and API or quota limits at the backend. It always backs up and uploads your photos at FULL resolution and original size. To sync and backup Mac Photos to Flickr, you just need to download and install "PicBackMan Flickr Uploader for Mac" on your Mac and connect your Flickr account.
Quick Tip to Backup your Digital Photos
If you have treasured photographs, or you take photos of everything you like, you won't want to lose them. So, what is the best way to backup photos on an ongoing basis? In the back of your mind, you know you need to backup all of your photos. But where do you start? Here's how to backup your digital life: PicBackMan is the easiest and simplest way to keep your videos safely backed up in one or more online accounts. Simply download PicBackMan (it's free!), register your account, connect to your online store and tell PicBackMan where your videos are - PicBackMan does the rest, automatically. It bulk uploads all videos and keeps looking for new ones and uploads those too. You don't have to ever touch it.