Image Search is the ability to search on a term and find images related to what you typed. Most search engines offer it, and it's great. But what if you have an image and want to know its origin? Or find similar photos? That's a reverse image search.

Google's reverse image search is a breeze on a desktop computer. Go to images.google.com, click the camera icon, and either paste in the URL for an image you've seen online, upload an image from your hard drive, or drag an image from another window.

But what about when you're on a mobile device and want to do a reverse image lookup? There are options.

Google Reverse Image Search on Mobile

Google built a reverse image search function into phones and tablets, albeit on a limited basis.

When you fire up images.google.com on mobile, the camera icon won't show up in the search bar. To get it, you'll need to load the desktop version on your mobile device while in the Chrome browser app for iOS and Android. Scroll to the bottom, tap the three-dot menu, and select Request Desktop Site. That will load the desktop verison, and the camera icon will appear, so you can upload photos from your camera roll.

Depending on your phone, Chrome also supports a reverse image search workaround. When you have the image you want to search, hold your finger on it until a pop-up menu appears; pick "Search Google for This Image" at the bottom. Note: This will NOT work in the Google app or other browsers (not even in Safari). It only works in Chrome. It also doesn't seem to work on newer iPhones; you'll need one with 3D Touch.

If for some reason this doesn't work, you can also select Open Image in New Tab. Then copy the URL, go back to images.google.com, and paste in the URL.

With either method, the results of a reverse image search then appear; you may have to click on a "More sizes" option at top to see only the images. You'll get options to narrow your query, such as finding animated GIFs, clip-art equivalents, or looking by the color scheme used in the original image.

Google Lens also offers a reverse image search option. Lens has its own app, but is also part of the Google app and Google Assistant, on both iOS and Android. You can recognize it by the icon that looks like this:

. The thing is, Lens is really more about helping you perform tasks, like instant translation, identify things, or find a product to buy, than it is for finding a source image.

Bing Visual Search on Mobile

That other big search engine, Bing from Microsoft, also does reverse image searches, but calls it "visual search." There is a icon in the search box at the top of www.bing.com/images that looks kind of like a camera. Click and it asks for an image URL, to upload a picture, or drag in an image.

The setup is the same on mobile; click Bing's camera icon on any mobile browser. A pop-up says that in order to search with an image, you'll need to give Bing access to your camera; accept or decline with a tap.

On the next screen, tap the Browse button on the bottom left. A pop-up menu will let you take a photo, browse your photo library, or browse third-party services. Tap browse to find photos stored in third-party services like iCloud Drive, Google Drive, and Dropbox.

The latest versions of the Bing app (iOS and Android) let you snap a photo and image search it immediately. You can upload a photo from your camera roll, scan a QR code, or point your camera at text or math problems (cheaters!). Tap the magnifying glass icon on the load screen, tap the camera up top, and choose how you want to search.

Third-Party Image Search Engines

There are a few search engines out there dedicated to looking up just pictures, but not all of them work directly with your smartphone or the default browsers.

TinEye

It's crawled over 36 billion images to date. TinEye allows search by URL, upload, or drag and drop on the desktop. On mobile, just click that upload (up arrow) icon to get options to take a photo, use one from the library, or upload from third-party services.

Yandex

Russia's Yandex search engine looks a bit like Bing-goes-Cyrillic. It has a unique image search that works on mobile devices right from the browser. Click Images, tap the camera icon in the search bar, and you get the usual options: take a photo, upload a photo, or find a photo in a third-party service.

There are also search engines geared specifically toward helping creatives find out if their creative work has been stolen. Check out Berify and Pixsy for options. Be warned, using them might cost you. However, they'll also track stolen images for you automatically and offline, alerting you if an image of yours is used without permission. Then you can go collect on the theft, and that makes them worth using.

Apps for Reverse Image Search

If you prefer apps over the browser, go directly to a reverse image search tool you keep on your smartphone at all times.

CamFind
Free for Android and iOS
This is a basic tool for taking shots with your smartphone and searching for similar items, as well as getting price comparisons if it's a product shot.

Search By Image
Free for Android
You can manipulate an image all you want before uploading via this app to get results from Google, Bing, TinEye, and Yandex.

Reversee
Free for iOS
This app sends your pics directly into the Google Images database to search for similar images, but upgrade to the pro version for $3.99 and get results from Bing and Yandex as well.

Reverse Image Search Extension
$0.99 for iOS
This one isn't an app you go into, but rather an app that adds an extension to other apps. It will put one of those extension buttons inside Photos and Facebook and other apps, so along with Copy or Send, you'll have an option to Search Image. Results appear in your mobile browser, and come from Google, TinEye, and Yandex.