I entered the contents in the file_field (for images) and text_area (for contents) created by form_for and saved it, but the image and the contents entered in the text_area are not drawn and the empty post and delete links are not saved. Will only be drawn.
Even if you check it with the developer tool, the content is empty, and the image is not drawn if there is no image data with the postfix if, so it is not drawn.

Create for image posting
class PhotopostsController</pre>
<strong>Partial for posting images</strong>
<pre><code><% = form_for (@photopost) do | f |%>
<span>
  <% = f.file_field: picture%>
</span>
  
  <% = f.text_area: content, placeholder: "Add comment"%>
  
<% = f.submit "Post", class: "btn btn-success"%>
<% end%>

<li>
<% = link_to gravatar_for (@ photopost.user, size: 50)%>
<span><% = link_to @ photopost.user.name, photopost_path%></span>
<span>
  <% = image_tag @ photopost.picture.url if @ photopost.picture?%>
  <% = @ photopost.content%>
</span>
<span>
 <% = link_to "delete", photopost, method:: delete,
                                      data: {confirm: "You sure?"}%>
</span>
</li>

class MypagesController

class Photopost

class User