Jerky scrolling with Images in UITableView - ios

Question

So I have been reading lots of solutions to this problem and it seems no matter what I do, I am still getting jerky scrolling in my UITableView when there are images present in my cells.
Here is a little info on how I am generating my cells.
I am calculating heights for the cells and cacheing the heights in height for row at index path
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
if let height = cachedHeights[indexPath.row] {
return height
} else {
let post = dataSource.items[indexPath.row]
var CellClass = FeedTableViewCell.self
if let RegisteredCellClass = cells[post.reusableIdentifier] {
CellClass = RegisteredCellClass
}
cachedHeights[indexPath.row] = CellClass.height(post)
return CellClass.height(post)
}
}
I have verified that the actual and calculated sizes are the same.
When configuring the cell in cell for row at indexpath, I setup all the elements and load the images asynchronously with SDWebImage
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if indexPath.section == 1 {
let post = dataSource.items[indexPath.row]
var wallCell: FeedTableViewCell?
if let registeredCell = tableView.dequeueReusableCell(withIdentifier: post.reusableIdentifier) as? FeedTableViewCell {
wallCell = registeredCell
if let postCell = wallCell as? FeedTableViewPostCell {
postCell.informationDelegete = self
postCell.actionDelegate = self
}
}
guard let cell = wallCell else { return FeedTableViewPostCell() }
cell.configureCell(post)
cell.delegate = self
return cell
} else {
return UITableViewCell()
}
}
Configure cell calls the method on the cell that populates the element with the post data. There is a sub view called mediaview that handles the images. If there are images int he post they are configured in that view like so.
for (index, element) in media.enumerated() where index < 3 {
addSubview(viewsArray[index])
viewsArray[index].setImage(with: element.source, placeholderImage: nil)
}
I read something about SDWebImage causing issues in it's default UIImageView extension so I wrote my own and this is the code for that.
func setImage(with url: URL?, placeholderImage: UIImage?){
if let placeholder = placeholderImage{
DispatchQueue.main.async(execute: {
self.image = placeholder
})
}
SDWebImageManager.shared().loadImage(with: url, options: [SDWebImageOptions.cacheMemoryOnly, SDWebImageOptions.scaleDownLargeImages], progress: nil, completed: {(image, data, error, cacheType, finished, url) in
if finished {
DispatchQueue.main.async(execute: {
self.alpha = 0
UIView.transition(with: self, duration: 0.1, options: UIViewAnimationOptions.transitionCrossDissolve, animations: { () -> Void in
self.image = image
self.alpha = 1
}, completion: nil)
})
}
})
}
If I comment out the block in mediaview that sets the image, my scrolling is perfectly smooth so I know it's not another portion of the cell generation. My understanding was that the asynchronous loading should alleviate the scrolling lag but I have attempted just about everything to no avail. Any help or insights on this would be greatly appreciated.