You should use alloc init like UIImage* myImage = [[UIImage alloc] initWithCGImage:myCGImage];
or you could try this:
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
NSUInteger width = CGImageGetWidth(image);
NSUInteger height = CGImageGetHeight(image);
NSUInteger bytesPerPixel = 4;
NSUInteger bytesPerRow = bytesPerPixel * width;
NSUInteger bitsPerComponent = 8;
int size = height*width*bytesPerPixel;
unsigned char *rawData = malloc(size);
CGContextRef context = CGBitmapContextCreate(rawData,width,height,bitsPerComponent,bytesPerRow,colorSpace,kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
CGColorSpaceRelease(colorSpace);
CGContextDrawImage(context, CGRectMake(0,0,width,height),image);
UIImage *newImage = [UIImage imageWithCGImage:CGBitmapContextCreateImage(context)];
CGContextRelease(context);
free(rawData);