The photos were posted by French site Nowherelse.fr and they apparently confirm some of the rumors that have circulated lately.
First of all, the edges seem to be more rounded, much like in the case of the iPhone 5C.
The volume buttons seem to get a new form, more rectangular and thinner, similar to the fifth-generation iPod Touch.
In addition, the power button is no longer on the upper side as in previous iPhone models, but on the right side of the case.
The new position of the on/off button is likely motivated by the possibility of one-handed operation of the smartphone.
The site wrote that the source who had sent them the photos noted that the cases were built based on data supplied by the manufacturer, but that these measurements may also change in the production phase.