The following code help your image to move using UIPanGestureRecognizer. While moving your selected image other images set there location automatically.

-(void)addImageToScrollView
{
        float x=5,y=40,width = 100,height = 100,spaceH = 5,spaceW = 5;
        for (int i = 1; i <= imageArray.count; i++) {

            [scrollView addSubview:[self getImageView:CGRectMake(x, y, width, height) forImageName:[imageArray objectAtIndex:i-1] forTag:i]];


            if (i%3 == 0 ) {
                x = 5;
                y = y+height+spaceH;


            }else{
                x = x+width+spaceW;
            }
        }

        [scrollView setContentSize:CGSizeMake(320, 1000)];

 }


-(CustomView *)getImageView:(CGRect)frame forImageName:(NSString *)imageName forTag:(int)tag{    
        CustomView *imageView = [[CustomView alloc]initWithFrame:frame];
        imageView.delegate = self;
        [imageView.imageView setImage:[UIImage imageNamed:imageName]];
        imageView.tag = tag;
        UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanImage:)];
        imageView.userInteractionEnabled = YES;
        [imageView addGestureRecognizer:pan];
        return imageView;
}

- (void)handlePanImage:(UIPanGestureRecognizer *)sender
{
    static CGPoint originalCenter;
    static CGPoint originalCenter2 ;

    static CGPoint newCenter;
    if (sender.state == UIGestureRecognizerStateBegan)
    {
        originalCenter2 = sender.view.center;
        originalCenter = sender.view.center;
        sender.view.alpha = 0.8;
        [sender.view.superview bringSubviewToFront:sender.view];
    }
    else if (sender.state == UIGestureRecognizerStateChanged)
    {
        CGPoint translation = [sender translationInView:self.view];

        sender.view.center = CGPointMake(originalCenter.x + translation.x, originalCenter.y + translation.y);
        UIView *view = [self checkImageContained:sender.view.tag];
        if (view) {
            newCenter = view.center;
            originalCenter2 =[self shiftImage:sender.view.tag tilTag:view.tag frame:originalCenter2 uiview:sender.view];
        }else{
            UIView *view = [self checkImageContainedinReverse:sender.view.tag];
            if (view) {
                newCenter = view.center;
                originalCenter2 =[self shiftImagereverse:sender.view.tag tilTag:view.tag frame:originalCenter2 uiview:sender.view];
            }
        }


    }
    else if (sender.state == UIGestureRecognizerStateEnded || sender.state == UIGestureRecognizerStateCancelled || sender.state == UIGestureRecognizerStateFailed)
    {
        [UIView animateWithDuration:0.2 animations:^{
            sender.view.alpha  = 1.0;
        }];
    }
}

-(UIView *)checkImageContained:(int)tag{
    CustomView *view = (CustomView*)[scrollView viewWithTag:tag];
    for (int i = 1; i <= imageArray.count; i++) {
        if (tag == i) {
            continue;
        }

        CustomView *vv = (CustomView*)[scrollView viewWithTag:i];


        if (CGRectContainsRect(vv.frame, view.frame)) {
            return vv;
        }
        if (vv.tag>view.tag) {
            float x = vv.center.x - view.center.x;
            float y = vv.center.y - view.center.y;
            if (x<20&& x>-20 && y<20 && y>-20) {
                return vv;          
            }
        }

    }
        return nil;
}
-(UIView *)checkImageContainedinReverse:(int)tag{
    CustomView *view = (CustomView*)[scrollView viewWithTag:tag];
    for (int i = 1; i <= imageArray.count; i++) {
        if (tag == i) {
            continue;
        }

        CustomView *vv = (CustomView*)[scrollView viewWithTag:i];
        if (vv.tag<view.tag) {


            NSLog(@"vv %f %f %f %f",vv.center.x,vv.center.y,view.center.x,view.center.y);
            float x = vv.center.x - view.center.x;
            float y = vv.center.y - view.center.y;
            if (x<20&& x>-20 && y<20 && y>-20) {
                return vv;


            }
        }

       }

    }
    return nil;
}


-(CGPoint)shiftImage:(int)startTag tilTag:(int)endTag frame:(CGPoint)previousFrame uiview:(UIView *)originalView{

        CGPoint nextFrame;
        CGPoint pp = previousFrame;
        if (startTag < endTag) {
            for (int i = startTag+1; i<=endTag; i++) {
                UIView *view = (UIView *)[scrollView viewWithTag:i];

                nextFrame = view.center;

                view.tag = i-1;

                [UIView animateWithDuration:0.2 animations:^{
                view.center = pp;
                }];
                pp = nextFrame;
            }
            originalView.center = pp;
            originalView.tag  = endTag;
        }
    return pp;
}
-(CGPoint)shiftImagereverse:(int)startTag tilTag:(int)endTag frame:(CGPoint)previousFrame uiview:(UIView *)originalView
{  
    CGPoint nextFrame;
    CGPoint pp = previousFrame;
    if (startTag > endTag) {
        for (int i = startTag-1; i>=endTag; i--) {
            UIView *view = (UIView *)[scrollView viewWithTag:i];

            nextFrame = view.center;

            view.tag = i+1;

            [UIView animateWithDuration:0.2 animations:^{
                view.center = pp;
            }];
            pp = nextFrame;
        }
        originalView.center = pp;
        originalView.tag  = endTag;
    } 
    return pp;
}