CoSy - Contact Sync for WhatsApp is a useful Android app developed by Michael Flisar. This free app allows you to sync your WhatsApp friends' profile images with your local phone contact images.

Please note that this app only works with a rooted device, so make sure your device is rooted before downloading and using it. If you're not familiar with what rooting is or if your device is not rooted, this app is not suitable for you.

The process is simple and can be done in three steps. First, save your friends' profile images in your gallery. Then, link your contacts with your WhatsApp friends by telling the app which WhatsApp friend corresponds to each phone contact. Finally, sync your images.

CoSy offers several functions to enhance your experience. You can sync WhatsApp profile images with your phone contacts, link contacts based on name similarity for a quick setup, and sync images automatically or manually. You can also choose to sync images only when your phone is charging or connected to WLAN. Additionally, you have the option to tint images before setting them as contact images and save image history, allowing you to go back to previous contact images.

Please note that CoSy is not affiliated with, associated with, or sponsored by WhatsApp. All of WhatsApp's images, icons, copyrights, and assets are the property of WhatsApp.