Do you have Google account? If you have created Google account and set up with Android device, then you can sync your Google account with your Android device. If you have synced your Google account with Android device and syncing Picasa Web album is enabled, then you will be able to see your photos from Picasa account on your Android device's gallery. You can also easily delete your Picasa photos from your Android device. If you are looking for a step by step process to delete Picasa photos from Android device, read below.
You can install PicBackMan's Picasa uploader for Mac from the website and start backing up photos and videos.
Quick Tip to Keep your Photos Safe
Making backups of your photos & videos is a chore you probably skip, but it really doesn't have to be hard. Here's an effortless way to backup photos - PicBackMan. 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.