When we upload photos to Flickr, it gets re-sized into different sizes to display on the site. Like thumbnails and small / medium / large size etc. The resizing of photos also depends on how big your device display screen is and whether or not you have your browser set to full screen.
What we see on a laptop is different from what you'll see on your phone or tablet. The maximum photo size that you can upload to Flickr is 200MB and the ideal size could be somewhere around 2048 pixels.
You can install PicBackMan's Flickr Photo uploader for Mac from the website and start backing up photos and videos.
Quick Tip to ensure your Photos never go missing
Photos are precious memories and all of us never want to ever lose them to hard disk crashes or missing drives. PicBackMan is the easiest and simplest way to keep your photos 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 photos are - PicBackMan does the rest, automatically. It bulk uploads all photos and keeps looking for new ones and uploads those too. You don't have to ever touch it.