This ticket is a followup of the following ticket T307058 and specifically on this discussion on the ticket: https://phabricator.wikimedia.org/T307058#8279372

AC:

• Do not allow images to take up more height than available width / 0.85
• Images are free to resize as needed for rendering below that maximum height
• Taller images (than said maximum height) will be top-aligned & button will be cut off
• The appropriate height will immediately be set, before the image is even loaded, to prevent content from jumping around
• While image is being loaded, the soon-to-be-image space will be grey.