Resizing Images for Alamy Using Photoshop

The purpose of this document is to try and shed some light on the process of upsizing images for Alamy. This, as a lot of people seem to be confused and asking the same question over and over. Let’s begin…

Definitions

To fully grasp the process, we first have to get some definitions for the purposes of this document:

Image size: Is the pixel size of your image as seen when opened in Photoshop or any other image editor or viewer. For example, the native image size of a picture produced by the Canon 20D is 3504 x 2336 pixels. If you do multiply that results in: 8,185,344 pixels or 8 MP (Megapixels).

File Size: Is the “weight” of your file as seen on the Windows Explorer (or the file explorer on the OS of your choice).

Resolution: As used in Photoshop, this refers to the number of pixels per inch. This is purely a printing reference value, as a digital image will have a defined number of pixels regardless of what this field says.

Note

This process should be done as the last step of your workflow and with your image at 8 bit.

The process

So let’s say we have an image which is 3504 x 2336 pixels. We open it in Photoshop and go to the Image > Image Size menu. We’ll get a window like this one:

We can see three areas: Pixel Dimensions, Document Size and Resampling area.

The Pixel Dimensions area tells us, well, the pixel dimensions of the image, in this case 2336 x 3504 pixels, as it is a vertical image.

The document size area shows us that this image will print, when printed at a resolution of 240 pixels per inch, at a size of 9.732 in x 14.598 in. Alamy want us to sumbit images that are upsized to pixel dimensions of at least 48mb at 300 pixels per inch.

The important thing here is that this refers to the pixel size and not the file size.

So what do we do first? The first thing would be to set the resolution to 300, but without changing the image size at this time. So we un-check the Resample Image box:

And set the resolution to 300:

We press OK and the re-open the dialog box, going again to the Image > Image Size menu.

You can note several things here:

1. The Pixel Dimensions didn’t change. This is because we un-checked Resample Image. This is what we wanted.
2. The Resolution now reads 300 pixels/inch as Alamy asks for.
3. The printing size changed. It is now 7.787 in x 11.68 in. Actually, the resolution of the print media varies a lot, so this is just a guide.

Now let’s check again the Resample Image checkbox:

We will now resize or upsize the image to comply with the 48MB pixel dimension that Alamy asks for.

An easy way to do this is to change the Width and Height units from pixels, to percent:

Now, when we change the percentage, the Pixel Dimensions will (of course) change, let’s see:

We’ve changed it to 140%. Now we can see that the Pixel Dimensions have changed. From 23.4M to 45.9M. Are we good to go? No, because Alamy asks for at least 48M and this image would be rejected.

So we try another number:

Now, as you can see, the Pixel Dimensions are 52.7M. Are we good to go now? Yup! It now exceeds what Alamy asks for. If you want it to be *exactly* 48MB as Alamy asks, you can play with the percentage value.

Now, the image size complies with Alamy requirements. And, no matter what format you save it in, the image size will be what you see in this dialog box.

The File Size will vary, but the Pixel Dimensions are what matters.

By the way, using percentages instead of pixel values when resizing allows you to write an action for batch resizing. That way, you’ll never forget to upsize one of your images, which would cause a whole submission to be rejected.

Conclusion

I hope this brief tutorial helps with upsizing images for Alamy. If you have any question, please write me so I can answer it right here and benefit other photographers.