From http://stackoverflow.com/questions/11739007/how-can-i-add-a-text-on-an-image-in-iphone

Add text to Image

-(UIImage *)addText:(UIImage *)img text:(NSString *)text1{
int w = img.size.width;
int h = img.size.height;
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(NULL, w, h, 8, 4 * w, colorSpace, kCGImageAlphaPremultipliedFirst);
CGContextDrawImage(context, CGRectMake(0, 0, w, h), img.CGImage);

char* text= (char *)[text1 cStringUsingEncoding:NSASCIIStringEncoding];
CGContextSelectFont(context, "Arial",20, kCGEncodingMacRoman);
CGContextSetTextDrawingMode(context, kCGTextFill);
CGContextSetRGBFillColor(context, 0, 0, 0, 1);
CGContextShowTextAtPoint(context,10,10,text, strlen(text));
CGImageRef imgCombined = CGBitmapContextCreateImage(context);

CGContextRelease(context);
CGColorSpaceRelease(colorSpace);

UIImage *retImage = [UIImage imageWithCGImage:imgCombined];
CGImageRelease(imgCombined);

return retImage;
}