Photo Mosaic




Introduction: Photo Mosaic

About: Currently attending Georgia Institute of Technology and studying electrical engineering.

Last year I wanted to make something special for my one year anniversary. I wanted to make something that showed our past year. I decided on a photo mosaic but I couldn't find a good guide on how to make one. After playing around with photoshop and bridge this how I made a photo mosaic. The total cost of this project was under $30.

 Tools needed:
     Adobe photoshop cs4 or newer 
     Adobe bridge 
     Some photoshop knowledge

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Step 1: Software

I really wanted software that would do most of the work for me and I found that in Adobe photoshop cs4 and bridge. Adobe changed the location of the contact sheet in cs4 from photoshop to bridge. If you have photoshop cs3 or earlier this instructable will not work for you.

Other ways to do it - If you don't have photoshop cs4 or newer you can try using "AndreaMosaic" software. It is a FREE mosaic software.
I didn't really like the mosaic it made using my photos. I really like the customization photoshop gave.

Step 2: Setting Up Main Photo

Choosing Main Photo-  The main image is the larger Photo in the mosaic. It works better if the photo is close up. If the image you have chosen isn't as zoomed in as desired, open up Photoshop and open the main photo. To do this, select File>open then choose the correct file. Select the crop tool and crop the image to the desired look. (see above image for location of crop tool)

Sizing Main Photo - Now you need to think ahead to what size you want the final print so that the final print isn't distorted.  I wanted my print to be 20"x30". To keep the ratio the same for the image I was working on and the final image, (The ratio will change based on your final photo size) I took 20/30=.6666667. That gave me the ratio I needed to crop my image.  I first re-sized the width of the image to 600px.
Image>Image Size-  Set the width (if the photo should be landscape) or the height (if the photo should be portrait ) to 600px.
Then crop the image so it has the of .66667. I took 600 *.666667=400. (see first image)
Image>canvas size-  If the photo is landscape, set the width to 600px and the height to 400px. If the photo is portrait, set the height to 600px and the width to 400px. For my photo I chose landscape.(see second image)
Save the photo.

Step 3: Setting Up Background Photos

Background Photos-  I have found if you use 1024 (32x32) photos, it makes the perfect balance of the main photo's resolution and size of the back ground photos.
Make 2 folders on your desktop or other desired location. Name one "Original Photos" and one "Resized Photos". Copy all the photos for the background in to the file called "Original Photos". I only had about 250 photos. To see how many photos are in the the file Right click "Original Photos">properties  and look for "Contains"  The number of files is how many photos are in the file. Since 16^2 is 256. I copied 6 photos to make the total number of files 256 (16x16). It takes four 16x16 to make a 32x32. It is best to make the images the highest multiple of 32. For example if you only have 60 photos the highest multiple would be 64(8x8) it will take 16 8x8 photo squares to make up a 32x32 square. 

If these multiples are confusing to you, for now just make the total number of photos in the "Original Photos" file equal 8, 64, 256, or 1024.

Step 4: Resize Background Photos

Open up photoshop.
Open the action panel if it is not open. To do this click Window>Actions.
Open up one of the background images (any one will do). 
Now click on the create new action button (see second image). Name the action "ResizeBGPhotos". Click Record .
Click Image>Image size Change the Resoluton to 300 px/inch (see third image.)
Click Ok .
Click Image>Image size  Change the  Width: 300px Height: 200px (if the main photo is landscape) and Width:200px Height: 300px (if the main photo is portrait). This is the same H/W ratio as the main photo (see fourth image.)
Click Ok.
Click File>Save as and save the file where ever you would prefer. Save as high jpg.
In the actions panel, click the square at the bottom to end the action.
Close the photo.
Click File>Automate>Batch  (See batch Image for Set up). Click Ok.
Wait till Photoshop is done automating(may take a few minutes). 

Step 5: Adobe Bridge

This is an example of how to do a 16x16. Adjust the settings and methods if using any other size.

Open up Adobe bridge.
Set the work space to "output" (press Ctrl+F4 ).
On the folder panel,  (left side of screen) select "Resized Photos" file.
In the content panel,  press Ctrl+A to select all photos.
Press Refresh Preview to view any changes made to the image.
In the output panel, use these settings:
Template : custom
Page Preset : custom
Size : custom
The Width and Height varies on the number of photos and orientation of the main photo. Play around with these numbers to get the photos as close together as possible. Here is what my photo used.
Width :2700 px
Height : 2000 px
Background : The goal is to make the image look like they are not a background. If the main photo is darker, set the background color to black. If it is lighter, use a lighter color or white,
Image Placement:  Save one as across and save one as down to make the order of photos not seem them same.
Columns X Rows : This is the square root of the number of images.
I had 256 images= 16x16, 64 images = 8x8, 1024 images=32x32.
Horizontal, vertical, top, bottom, left, right: 0 px
Use Auto-Spacing: unchecked.
Save : Scroll down to the bottom and press save.

You should have 2 Pdf Files saved at this point.

Step 6: Finish Background Images

This uses four 16x16 images to make up a 32x32 image.

Open both pdf files in photoshop. See Image for Settings.
Use the crop tool to trim off the outside boarder. Do this to both pdf files.
Make a new File( File>New ).
Save the name as "Mosaic".
Set the width and height to the same size in inches as the size you want to print. (mine is width: 30 height: 20) 
Set the resolution  to 300 px/in.
Click Ok .
Go to one of the pdf files in photoshop and select all (Ctrl+A ) then copy it (Ctrl+C ).
Go to the file called "Mosaic" and paste the image (Ctrl+V ). Align the image with the top left. (Look at images above for example.)
Now do the same with the other pdf file. Align this image next to the first pdf.
Flatten the layers(Layers>flatten image ).
Select all (Ctrl+A ) copy (Ctrl+C ) and paste (Ctrl+V ).
Use the Move Tool  to align the pasted image along the bottom.
Flatten the layers(Layers>flatten image ).
Save the image(file>save ).

Step 7: Finish Mosaic

Open the "Main" photo that was saved in step 2.
Click Image>Image size and set the image to be the size of the final photo. In this example, I set the width to 30 in. and the height to 20 in.
Select all (Ctrl+A ) copy (Ctrl+C ) and paste (Ctrl+V ) the "Main" photo into the mosaic image in photoshop.
In the mosaic File select the layer that was just pasted in and change the blending mode to hard light(see second and third images.)
This will give a rough looking mosaic(see forth image.)
Every photo will be different. Play around with Image>Adjustments>curves , blending modes , and the opacity to get the desired look.
Save the photo as .jpg.

Step 8: Printing Image and Frame

I used walmart's photo center to print my photo.
It was $16 for the print with in store pickup. It took about a week for them to print and ship it to the walmart.
As for the frame, I just picked up a basic black frame at walmart when I picked up my photo. The frame costed $10
I added rhinestones on the outside for a personal touch.

Step 9: Other Examples

These are some examples of other mosaics I have made for friends and family.

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    7 Discussions


    3 years ago

    Thanks coaleu for the nice method; Just a small caveat - this method doesn't make true photo mosaics. It basically makes a grid of photos and superimposes the original photo.

    To make "true" photo mosaics that don't superimpose the original photo I would recommend using TurboMosaic software. You can find it here:

    I have attached a sample true photo mosaic I made using TurboMosaic. I have also attached a zoomed screenshot.


    5 years ago on Introduction

    Very nice method, indeed.

    I've been doing some improvement by combining your method and andreamosaic's. So, instead of using batch photoshop, I made the small images using andreamosaic program. Then, i fix the image using your method (curve, level, etc). And the result is quite perfect.


    7 years ago on Introduction

    Thanks Coaleu,
    This is a very interesting technique. Thank you!

    I have been recommending Andrea's Mosaic to everyone. I have an awesome picture of my Nikon D90, made up of many of my photos, drawings and painting. The program was free and worked perfectly!



    wow... I always wonder how they do that. I must try this once I have time


    Reply 8 years ago on Introduction

    While this is a good and cheap option to Photo Mosaics, it is NOT a true photo mosaic. This utilises a semi transparent layer of photos super-imposed over an existing photograph. A true photo mosaic uses a folder containing a number of source photos and uses those photos to create a new image which matches a target image based on lighting, colours and shadows. For an example of a photo mosaic can be seen here -

    That being said, the Coaleu's 'ible is well documented and an easy alternative.



    Reply 8 years ago on Introduction

    Thanks, let me know how it goes.