image processing resolution reduction
<p>I'm working on a program of image processing and I need to apply different filters on an image imported from photo library, there's a list of buttons representing the different filters and I want the image that will be processed to appear in the button as an icon (same as instagram filters). the problem is that the image is of high resolution so when I try to use it as an icon for the button it appears as just a blue rectangle..anyone can help solving this issue pls?
thanks[as it appears three button red, green, blue appeared as a blue filter as u can see][1]</p>

<p>The next stage of the app is to control the intensity of the applied filter ( each filter is used to boost a specific colour in the image, now I only work on three main filters red, green, and blue). I need to control this intensity using a slider. The code looks very easy, however it doesn't work and I can't notice any change when I move the slider to control the intensity.</p>

<pre><code>@IBAction func onSlider(sender: UISlider) {

    var factor = Int(Slider.value)

    if red.selected == true {

        RedAmpFactor = factor

    } else if green.selected == true {

        GreenAmpFactor = factor

    } else if blue.selected == true {

        BlueAmpFactor = factor
    }
</code></pre>

<p>The last stage will be to add more professional filters, is there any one has already coded some filters and can provide me with them as a guide?</p>