I want my noPreviewView it to appear just when there is no smallThumbnail available, but the noPreviewView always appears...

It is not with != nil ????

If I delete the "if" ... "else", and just leave the asyncImage it works perfect... so it must be something about the != nil I think...

HStack {

                        if book.volumeInfo.imageLinks?.smallThumbnail != nil {
                            NoPreviewView()
                                .frame(width: 130)
                                .scaledToFit()
                        } else {
                            AsyncImage(url: URL(string: (book.volumeInfo.imageLinks?.smallThumbnail)!)) { image in
                                image
                                    .resizable()
                                    .scaledToFit()
                                    .clipShape(.rect(cornerRadius: 15))
                            } placeholder: {
                                ProgressView()
                            }
                            .frame(width: 100, height: 200)
                        }

                        Text (book.volumeInfo.title)
                    }

You said that you want the NoPreviewView to show when there is no smallThumbnail unavailable... Perhaps you have the logic backwards? Try switching != nil to == nil...

You would be better to do a if let then you would not have to force unwrap the URL - safer.

if let url = URL(string: (book.volumeInfo.imageLinks?.smallThumbnail) {
  AsyncImage(url: url) // etc
} else {
  // no preview
}

Hi @NigelGee !!!!

I am trying your advice, but It forces me to unwrap it... what am I doing wrong? it says:

Value of optional type 'String?' must be unwrapped to a value of type 'String'

Insert '!'

if let url = URL(string: (book.volumeInfo.imageLinks?.smallThumbnail)) {
                            AsyncImage(url: url) { image in
                                image
                                    .resizable
                                    .scaledToFit()
                                    .clipShape(.rect(cornerRadius: 15))
                            } placeholder: {
                                Image("placeholder")
                                    .resizable()
                                    .scaledToFill()
                            }
                            .frame(width: 100, height: 200)

                            Text (book.volumeInfo.title)

                        } else {
                            NoPreviewView()
                        }

Try

if let urlString = book.volumeInfo.imageLinks?.smallThumbnail, url = URL(string: urlString) {
  AsyncImage(url: url) { image in
      image
          .resizable
          .scaledToFit()
          .clipShape(.rect(cornerRadius: 15))
  } placeholder: {
      Image("placeholder")
          .resizable()
          .scaledToFill()
  }
  .frame(width: 100, height: 200)

  Text (book.volumeInfo.title)

} else {
  NoPreviewView()
}

@NigelGee If I try that, it shows error there and also in the foreach...

As I do not have the code, think I missed a let before let url = URL(string: urlString)

Try removing the optional chain book.volumeInfo.imageLinks.smallThumbnail