Image Dimension

NSURL *imageFileURL = [NSURL fileURLWithPath:...]; // Put your image in a URL
CGImageSourceRef imageSource = CGImageSourceCreateWithURL((CFURLRef)imageFileURL, NULL);
if (imageSource == NULL) {
// Error loading image
...
return;
}

CGFloat width = 0.0f, height = 0.0f;
CFDictionaryRef imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, NULL);
if (imageProperties != NULL) {
CFNumberRef widthNum  = CFDictionaryGetValue(imageProperties, kCGImagePropertyPixelWidth);
if (widthNum != NULL) {
    CFNumberGetValue(widthNum, kCFNumberCGFloatType, &width);
}

CFNumberRef heightNum = CFDictionaryGetValue(imageProperties, kCGImagePropertyPixelHeight);
if (heightNum != NULL) {
    CFNumberGetValue(heightNum, kCFNumberCGFloatType, &height);
}

CFRelease(imageProperties);
}

NSLog(@"Image dimensions: %.0f x %.0f px", width, height);