Replacing button images shows weird issue - ios

Question

I have two images I used for showing on/off. Everything was working perfectly. When my designer asked to replace the images, I replaced the images and replaced the name of the images in the class. Suddenly the switching isn't happening any more. I used [button setImage:image forState:UIControlStateNormal]; With condition. My condition is working perfectly. But image never changes. Replacing these images with the old images worked perfectly for the same code.
Now, I again replaced it back it to the new images and added setBackgroundColor for Button. Strangely the images are getting replaced. If I take away the backgroundColor method it doesn't work. Does anyone knows why this happens?? I think the image is getting set as background image as well. But I haven't used a single code anywhere to set the background image.
Update
This is the place I set the images. Where in viewDidLoad
selectedImage = [UIImage imageNamed:kcheckSelected];
notSelectedImage = [UIImage imageNamed:kcheckUnselect];
-(UITableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *identifier = #"cellIdentifier";
UITableViewCell *cell = [tableview dequeueReusableCellWithIdentifier:identifier];
if (cell == nil)
{
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identifier];
UIView *view = [[UIView alloc]initWithFrame:CGRectMake(15, 0, tableview.frame.size.width - 15, 1)];
view.backgroundColor = [UIColor lightGrayColor];
[cell.contentView addSubview:view];
}
NSString *sltd= [selectionArray objectAtIndex:indexPath.row];
UIImage *image = nil;
UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(tableview.frame.size.width - 60, 5, 60, 50)];
if ([sltd isEqualToString:#"yes"])
{
image = selectedImage;
}
else
{
image = notSelectedImage;
}
[button setBackgroundColor:[UIColor whiteColor]];
button.tag = indexPath.row;
[button addTarget:self action:#selector(selectButton:) forControlEvents:UIControlEventTouchUpInside];
[button setImage:image forState:UIControlStateNormal];
[cell.contentView addSubview:button];
[cell.contentView bringSubviewToFront:button];
User *userObj = [userArray objectAtIndex:indexPath.row];
cell.textLabel.text = userObj.name;
cell.textLabel.font = [UIFont fontWithName:#"Montserrat-Regular" size:17];
if ([userObj.installOnIpad boolValue] == YES)
{
cell.imageView.image = [UIImage imageNamed:#"ipad-icon-active"];
}
else
{
cell.imageView.image = [UIImage imageNamed:#"ipad-icon-disabled"];
}
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
return cell;
}