I am about to enter 5 images in an online photo contest. The image specification requires the images to be sized at 450KB, 72 dpi. The longest side of the image has to be a maximum of 1024 pixels. I cannot seem to get this low in total size, my images come to about 2MB when I type in the 1024 pixel requirement.

Would love some help here.

  • Dont forget to accept the answer when it worked.
    – SitiSchu
    Commented Jun 26, 2017 at 14:01

2 Answers 2


What format are you saving them in? From your description it sounds like you are using PNG.

Use JPEG - it's the best format for compressing large photographic images for the web. In Photoshop use Save for Web, set the file type to JPEG, make sure the convert to sRGB option is checked, set the quality slider at the highest, then if necessary reduce it until your file size is below 450kb.


I have met this question before, the last answer doesn't seem to perfect to me.

Maybe this website will help you more. It is TinyPNG .

What does TinyPNG do?

TinyPNG uses smart lossy compression techniques to reduce the file size of your PNG files. By selectively decreasing the number of colors in the image, fewer bytes are required to store the data. The effect is nearly invisible but it makes a very large difference in file size!

Why should I use TinyPNG?

PNG is useful because it’s the only widely supported format that can store partially transparent images. The format uses compression, but the files can still be large. Use TinyPNG to shrink images for your apps and sites. It will use less bandwidth and load faster.

It's free and convenient. Have fun :)

  • Isn't "Smart lossy compression" what JPG is all about?
    – xenoid
    Commented Jun 26, 2017 at 11:49
  • Yes. But as mentioned, PNG (and presumably TinyPNG) supports transparency. JPG does not. Commented Jun 26, 2017 at 14:33

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