Save Webcamtextures. Why running out of memory (ram)?

I know this is not a nice code but I need help with the overall problem that I am running out of memory (same happens if I use a LinkedList). What the code does is, that I save a picture around every 40ms till I have 1000 texture2Ds in an array and then start overwriting from the begin. But is seems that the overwritten textures are not deleted from the memory although they are out of scope.

     public RawImage display;
     public AspectRatioFitter imageFitter;
 
     public static Texture2D[] picArray;
     public static WebCamTexture webCamTex;
     public static int numberSavedPics = 1000;
     public static int counter = 0;
 
     private int firstPic = 0;
     private int lastPic = -1;
 
     void Start () {
         picArray = new Texture2D[numberSavedPics];
         WebCamDevice cam = WebCamTexture.devices [0];
         webCamTex = new WebCamTexture (cam.name);
         if (display != null) {
             display.texture = webCamTex;
             imageFitter = display.gameObject.GetComponent<AspectRatioFitter> ();
         }
         webCamTex.Play ();
     }
     
     // Update is called once per frame
     void FixedUpdate () {
         if (display != null) {
             float videoRatio = (float)StartScript.webCamTex.width/(float)StartScript.webCamTex.height;
             imageFitter.aspectRatio = videoRatio;
         }
 
         if (counter < numberSavedPics) {
             counter++;
         } else {
             deletePic ();
         }
 
         savePic ();
     }
 
     private void savePic(){
         Texture2D snap = new Texture2D (webCamTex.width, webCamTex.height);
         snap.SetPixels (webCamTex.GetPixels ());
         snap.Apply ();
         lastPic = ((lastPic + 1) % numberSavedPics);
         picArray [lastPic] = snap;
 
     }
 
     private void deletePic(){
         firstPic = ((firstPic + 1) % numberSavedPics);
     }