Pixels and Picture Quality

Photography is my new hobby. Based upon what I've read, once you reduce the size of a digital picture by reducing the number of pixels it originally contained (and then save the result), the picture quality suffers and those pixels are now irretrievable. In a landscape shot, for example, I find 1070 pixels in the horizontal plane to be perfect for my particular needs, and I save most of my shots in that size. Quality remains acceptable

If someone sends me a shot with, for example, 800 pixels in the horizontal plane and I want to boost it to 1070 pixels, I can do so very easily--and the photo will then grow to the desired size.

My assumption is that the newly added pixels in this example are neutral in nature and, instead of replacing quality pixels containing important data which were in the original shot, are now actually just filler and continue to decrease the quality of the shot.

Is this assumption correct?

Thank you very much for any light you may be able to shed on this subject.

Dan

Answer:

Dan, there are two basic ways of resizing or enlarging a photo using Photoshop or other image editing software. One is resizing without resampling and the other is resizing with resampling. While they are two different concepts it is important to understand their differences when deciding the best way to enlarge or reduce the size of your photo.

When you resize without resampling you are not changing the number of pixels in the photo, but you are changing the size of the pixels or how many pixels there are per inch (PPI). When you resize using this method you are not adding or subtracting digital information but are changing the actual size of the individual pixels. This method will not change the photo dimensions as you are doing but simply changes the resolution of the image.

The type of resizing you are referring to is resizing with resampling. When this is done the software uses complex algorithms to change the actual pixel count in the image. When you reduce the size of the image the software essentially removes pixels (downsampling) and when you make the photo larger the software adds pixels (resampling up). As you have already figured out when an image is made smaller those lost pixels cannot be later restored and when you make the image larger you are adding some pixels that to some degree or decrease the quality of the image.

Having said that the resampling algorithms used by today's photo editing software can do a very good job in resizing images with little noticeable loss of quality as long as you do not enlarge the image excessively.

About papixelhub

Hi there, I’m Prem Amrit ! I’m an entrepreneur and digital marketing consultant from Patna, India. I founded my own digital agency, where I help SMBs leverage social media, SEO, and content marketing to grow their traffic and generate qualified leads for their business. I started Papixelhub in 2019 as a side project to document all the strategies, tools, and tactics that I was using to grow my small agency. The goal was simple: to arm other solopreneurs with all the right information they needed to launch a successful business.