Farmis, the current limitation is 300KB of payload per single request. So, you'd need to make sure that your total payload (all images) size doesn't exceed this amount.

yes, you should compress it first. the image should < 300 kb, from my experiences.

Hello Farmis, an update on this. It is correct that every single image has a size limit, but also the overall endpoint payload has a limit per screen, which was recently increased to 10Mb (see Sept release change log. Sending a larger amount of data will result in an error in your flow.