Reduce image file size

Question

Is it possible to reduce the image size without changing dimension of image.Similar like photoshop does.

e.g If Actual image size 400Kb with dimension 400 X 300 and if I edit & save image has low resolution. Then the image size while be 250kb with dimension 400 X 300.

Note: I need to achieve transparency if image contains. I need to push this image server and the same image while be shown in website.

See this: http://stackoverflow.com/questions/9506871/image-compression-by-size-iphone-sdk — Adam, May 25 '12 at 10:49
@Adam thanks for your fast response. If I compress iamge into JPEG transparency part will become white right... — Anand, May 25 '12 at 11:06
Take a look at this http://stackoverflow.com/questions/1282830/uiimagepickercontroller-uiimage-memory-and-more — Parag Bafna, May 25 '12 at 11:21

score 4 · Answer 1 · answered May 25 '12 at 12:13

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yeah it is possible .... see this code

UIImage *image = [UIImage imageNamed:@"anyImage.png"];

NSData *data = UIImageJPEGRepresentation(image, 0.5);
// 0.5 is float value it is 1.0 for same resolution

UIImage *newImage = [UIImage imageWithData:data];

Thank You!

answered May 25 '12 at 12:13

TheTiger

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It removes transparency. Need to compress image with transparency. – Tushar - iOS developer Nov 28 '18 at 10:05
You can't @Tushar-iOSdeveloper. You can just decrease the image dimension in case of png. – TheTiger Nov 28 '18 at 10:15

score 2 · Accepted Answer · edited May 23 '17 at 11:58

gif or png images cannot be compressed. They implement a build in compression algorithm and that's it.

The best solution in your case would be to save the png image as a jpeg with a solid color replacing the transparent color, then compress the jpeg image and save it.

When you'll need the image, you will convert the jpeg image to a transparent image, by using the CGImageCreateWithMaskingColors core graphics function.

See this thread on how to make a color to transparent with core graphics

score 1 · Answer 3 · answered May 25 '12 at 12:02

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It may be worth taking a look at this. This is for jpegs, it really works, and the pictures look pretty much the same. http://www.jpegmini.com/main/home

answered May 25 '12 at 12:02

riseagainst

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Reduce image file size

3 Answers3