It creates an optical illusion, when being viewed from the distance you see the main picture, but when viewed closer you see the smaller pictures.
These effect is usually used in wedding photos, family photos, and many more.
For this tutorial we will be using a picture of a 1991 Mitsubishi GTO and fill it with smaller pictures of the same car.
Step 1: Crop the Part of the Picture We Want to Fill
After Selecting the area you want to be cropped, press Enter(Win)/Return(Mac) and that should leave you with the square area selected.
Next to work on the pictures that will be used to fill the main picture.
Step 2: Crop the Smaller Images
Grab your Crop Tool,C on the keyboard to select it.
Then go to the Options Bar , to enter in a value of 50px for the Width and Height.
Since we have already set the size for our crop tool, I dragged a selection around a part of the picture of your choice. No need to hold down shift this time since we have already set the size for our crop tool. Then press Enter(Win)/Return(Mac) to make the selection, then it will crop your selection and resize it to the size you entered in the options bar, in this case 50x50 px.
Then just repeat that for the other pictures you want to use, in this case I will just be using to pictures to fill my main picture.
After cropping all the pictures you want to use to fill the main picture, you should end up with something like picture4.
Step 3: Create a New Document
Go to File , then New , to bring up the new project dialogue box, you can also bring it up by Ctr + N (Win) / Command + N (Mac) . We want to create a new document that is twice the size of the smaller images we have cropped.
Since I cropped mine to 50x50px I will be creating a 100x100px document.
Also make sure that the resolution for your new document matches the resolution on your main image.To check for that, you go to Image menu, then Image Size . That option will show you the size of the document where you can see the resolution of the photo, under the Width and Height of the photo.
Step 4: Making the Pattern
Select the first small image then drag it to the new document.(First Picture)
Then Arrange the first picture to the top left of the new document, the photo should fit there like a puzzle piece.(Second Picture)
Click the new document and while holding Alt(Win)/Option(Mac) key then drag the photo to the bottom right of the new document. By holding the Alt or Option key it creates a copy of the layer being dragged, and you end up with two copies of the image across from each other.(Third Picture)
Drag the second small image to the new document then drag it to the top right of the image. (Fourth Picture)
Just like the previous step while holding Alt(Win)/Option(Mac) key then drag the photo to the bottom left of the new document.
Step 5: Flatten the New Document
First go up to the Layer Menu , then Flatten Imag e. Nothing really happens to the document it self, but it does change your Layers Palette and you end up with 1 layer instead of several layers.
Step 6: Making the Pattern
After Desaturating the image, it is now ready to be made into a pattern, or as Photoshop calls it Define a pattern. Go to the Edit menu, click Define Pattern, which should bring up a Pattern Name Dialogue box(Second Picture), name it what ever you want, ill be naming it "car". Then you can click OK. We don't need this document window anymore so we can close it.
Step 7: Now the Fun Part
Now its time to fill the page with the pattern we created, to do that we have to go to Edit menu, then click Fill , or use the shortcut Shift + F5
which will bring up a dialogue box.For the Use Option choose Pattern , then on the Custom Pattern Option click the little thumbnail and choose the pattern you have created. Just leave Blending Mode to Normal and Opacity to 100%. (Picture 1)
Photoshop will fill your whole document with the pattern.(Picture 2)
To blend the Pattern in with the image we just have to adjust the blend mode of the layer from Normal to Overlay .(Picture 3)
After changing the blend mode you will end up with something like(Picture 4), hopefully a little better.
Step 8: Hints & Tips, Example
Just a couple of Tips or reminders while making this, just make sure to be creative with it. If you are not satisfied with your work, experiment around with it use different sizes adjust the blend mode, and important thing to remember Take your time.
I tried it on a Model and that was my results, results will differ depending on the settings you set you can just play around with it and experiment around.