digital photo frame

Hey,

I would like to buy an e-ink device (probably an e-reader) to act as digital photo frame for black and white pictures. What device do you recommend to buy?

My requirements:

• good resolution, e.g. 300 ppi
• great contrast and at least 16 shades of gray
• WIFI enabled, so that it can download new pictures
• display of 7 inches or larger
• easy to hack the ScreenSaver

I would like to give the device to grandma, so that she can look at new pictures of her grandson. I saw an implementation with Kindle but don't want to worry about updates killing my jailbreak: https://marios-blog.com/2020/01/22/d...le-paperwhite/

Is there any reader I should consider? Thanks?