title: Prawn - image is cropped & full image not render
body: <p>I'm currently working on a Ruby on Rails 5.2 application using Prawn and CombinePDF. I make a request to get a file to the Box api. The file I get from box I then convert to string using <code>StringIO.new(image)</code> which I then add to a prawn document as shown.</p>
  
  <pre><code>attach_docs_from_submission(user_data).each do |file|
        image = client.download_file(file)
        format_image = StringIO.new(image)
        pdf_prawn = Prawn::Document.new
        pdf_prawn.image format_image
        pdf_data = pdf_prawn.render
        pdf &lt;&lt; CombinePDF.parse(pdf_data)
      end
  </code></pre>
  
  <p>However, when I check the PDF is not the full image. <a href="https://i.stack.imgur.com/ZxaM6.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZxaM6.png" alt="enter image description here"></a></p>
  
  <p>Is there a way to fit full size of image? is the issue coming from Prawn or CombinePDF?</p>