What is the optimal og:image size for sharing a link in Whatsapp (Slow image rendering)
It seems very easy to find the optimal size for sharing a link on Facebook. I have an app that shares to Facebook and the image shows perfectly. I'm using the same sizes for Whatsapp, but what happens there is that it takes the image too long to render in comparison to other sites I tried to share.
My first guess was the size, but if you have any other ideas for the slow rendering, it would be great!
Answer
According to the fb sharing guide the minimum size for the image is 200x200 This is what the guide says.
Use images that are at least 1200 x 630 pixels for the best display on high resolution devices. At the minimum, you should use images that are 600 x 315 pixels to display link page posts with larger images. Images can be up to 8MB in size.
If your image is smaller than 600 x 315 px, it will still display in the link page post, but the size will be much smaller.
The minimum image size is 200 x 200 pixels. If you try to use an image smaller than this you will see an error in the Sharing Debugger.
Here is a link to the guide. https://developers.facebook.com/docs/sharing/best-practices
You can try to compress the image by running it through an online compression tool like https://compressor.io/ or http://www.tinypng.com . Also you could try resizing the image to the minimum permitted 200x200 and see if that helps.