Yes, just by looking at the photo it is not easy to understand whether jewelry is made of silver or not.. Google also doesn't have clear instructions for this task, but I will try to help.
It has been almost a year since I have switched to online shopping (nearly fully). I know how important is to get what you see on the photo or better, but not worse. When it comes to silver jewelry, judging just by look might get really tricky. In IDenteco online store we always mention the material jewelry items are made of. Let's discuss where you will need to focus your attention.
Don't look for a sterling silver stamp 925 or try to study it carefully: the shape, clarity. If you noticed letters next to the numbers or you the stamp is not visible, then you are looking at fake silver. Keep in mind that nowadays, the 925 stamp doesn't mean anything. If you are buying handmade jewelry online, then most of the items might not bear 925 stamp, and I personally checked multiple times this kind of items myself and with the help of professionals who confirmed authentic silver and high quality despite the fact the magic numbers were missing.
Train the eye. Get into contact, study the authentic silver jewelry. Try to find different styles (enameled, ethnic blackened, with ornaments, sterling silver, etc.) The more you see, the more your eye will be trained to identify real silver. You will notice the difference very fast.
Finally, always check the price. As you see on the photo above, the ring costs 0.87 EUR and the description said it was sterling silver. I don't know who believes it, These prices cannot exist with the real silver jewelry.
Good luck in your online shopping! The "doors" of IDenteco are always open.