Why is Your PNG File So Big? [3 Possible Reasons]

There is a never-ending debate over which file format is the best. In truth, each one has its pros and cons when saving your images or graphics. JPEG seems to be the go-to for photography because the amount of detail in photographs can handle the slight quality loss that comes with the lossy compression of this file format. If you don’t want to suffer quality loss, then PNG is the way to go, but what is the downside?

PNG files tend to be much larger and therefore take up more space in your storage. The larger size is due to several reasons:

  1. Lossless Compression
  2. Too Many Colors
  3. Too Much Detail

Let’s look at each of these reasons and how they affect the size of the PNG file. There may be some solutions and workarounds for downsizing PNG files to save storage space on your hard drive.

3 Reasons PNG Files Are So Big

The disparity between the file size of a PNG file versus a JPEG file can be quite shocking when you first learn about it. A full-size PNG may be 402KB, as opposed to a full-size JPEG which can clock in at just 35.7KB. It all comes down to data— JPEG files are smaller because they contain less data.

If you’d rather forgo manually reducing the size of your image file, you can always use a compression tool, or you can opt into using premade graphic templates from a website like Placeit.net.

1. Lossless Compression

Lossless compression has to do with the data of an image. This compression style allows for an image to be compressed without any loss of information— meaning after you save an image and reopen it in any program, it will look the same. If you were saving the image as a JPEG, which uses a lossy compression style, some of the data would be downsized. As a result, when you reopen the file in any program, the quality of the image wouldn’t be the same.

The loss of quality may not be a noticeable difference, which seems to be the case with most photography. If that’s the type of image you’re dealing with, one that wouldn’t suffer from a little quality loss, and you would prefer more storage room, try saving your file in a JPEG format instead.

The JPEG format isn’t for you if your image requires transparency. Look at the next couple of reasons and solutions to help reduce your file size.

2. Too Many Colors

Since PNG works with a lossless compression style, the more data the image has, the bigger the file will be ultimately. A large amount of data could result from a few different factors— one being the number of colors in the image. PNG can be saved in indexed-color, grayscale, truecolor, grayscale with alpha, or truecolor with alpha. Alpha means that your image will have transparency.

Grayscale or indexed-color would be the ideal way of saving the image because it would result in a smaller file size than saving in truecolor. If your image is black and white, then a low color option like grayscale won’t affect the image. If you only have a few colors in your image, indexed-color will allow you to save your image with at least 256 colors. You can make these changes in any photo editing program you use.

If you go with the indexed-color option, you can expect the mode to choose the best 256 colors for your specific image and replace all your image pixels with an index of that chosen color palette. The results take the image down from 16 million colors to 256, and a side-by-side comparison will show very little if any, noticeable difference. However, the difference in the size of the file will be far more substantial.

3. Too Much Detail

Just like the number of colors affects the size of the file, so does the detail in the image. To give you an idea of how dramatic the difference is in the details, adding two pixels to the width of a PNG image can double its size. Large areas of flat colors compress better than complex detailed, or patterned areas. Therefore, simplifying the image will decrease the size of the file when saved.

Another way to reduce the size of your image is by assessing the negative space around your image. If the negative space isn’t adding to the overall image, eliminate it, and by doing so, you will downscale the size.

Lastly, if your image doesn’t require transparency but can’t save it as a JPEG, you can untick the transparency box when you save the image, which should reduce the size a bit because it’s one less chunk of data to retain.

How to Reduce the Size of Your PNG File

If you’ve gone through the suggestions mentioned above and they didn’t reduce the size of your file enough, or you couldn’t utilize the solutions for any reason, there is still an option for you. You can use a tool like a PNG compressor or optimizer.

Some of these tools will reduce the size by cleaning up the meta-data. Others will simplify the image for you, which has a more dramatic result but may compromise the quality of the image.

If you do your research, you can find an optimizer that will assist with the deflate stage of compression by providing better matches in your data to reduce the size of the image. Tools like these can reduce the size of your PNG by 5% and will not compromise the quality of the image.


PNG file format is known to take up a lot of storage due to its lossless compression style. What PNG lacks in space, it makes up for in quality, so it is up to you about what is more important. Worst comes to worst; you can purchase an external hard drive to store more images or do a regular purge to make room. Either way, there are options to reduce or accommodate the size of your file.