iOS returning image with different size?

Question

I want to upload an image up to 8 mb. so for testing I have added image in my photo gallery of size 4.2 mb (dimension : 3264 X 2443). But when I am picking that image for uploading, I have checked size of image. But it returning 9840076 bytes i.e. 9.3842 mb which is 4.2 mb in actual. So image of size 4.2 mb is not able to upload.

I have used below method to calculate size of image, and this is returning 9840076 bytes.

[UIImageJPEGRepresentation(imageRerurnedFromPhotoGallery , 1.0) length];

Am I doing something wrong in calculating size of image? Please suggest me the proper way. Thanks in advance!

I don't understand this: "it returning 9840076 bytes i.e. 9.3842 mb which is 4.2 mb in actual". — bdesham, Jun 03 '13 at 13:29
he is saying size of image is 4.2 MB but by that code he is getting 9.3 MB which is wrong — Prakash Desai, Jun 03 '13 at 13:41

score 0 · Answer 1 · answered Jun 03 '13 at 13:35

0

why dont you try like this?

you will get size in bytes

NSData *data = [[NSData alloc] initWithData:UIImageJPEGRepresentation((Your Image), 0.5)];

int imageSize = data.length;
NSLog(@"size of image is: %i ", imageSize);

answered Jun 03 '13 at 13:35

Prakash Desai

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3
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`UIImageJPEGRepresentation(..)` will return `NSData` instance which returns length in bytes. This is already mentioned by OP in the question. In above code you are in fact duplicating 4.2MB image data in the memory which is unnecessary. Only change you have is `JPEG quality = 0.5` which will slash the image pixels. – Amar Jun 03 '13 at 13:45

score 0 · Answer 2 · edited May 23 '17 at 11:43

You are decoding and then re-encoding the image, which is why the file size may be different. If you don't need to modify the image at all, use ALAssetsLibrary to get the image as an NSData object rather than a UIImage object. Then, when you look at the NSData's length property, your file size will match exactly. See Using ALAssetsLibrary and ALAsset take out Image as NSData for some sample code.

iOS returning image with different size?

2 Answers2