Repository: icetemple/genrss

Issue:
Genrss don't return image
<!-- Describe the bug -->
When i add image or image_url, genrss generate xml without image.

### To Reproduce
Steps to reproduce the behavior:
1. Init GenRSS object with arguments title, site_url, feed_url and image_url with any link.
2. try to get xml.

```python
image_url = 'https://s3.smartfridge.me/image.jpg'
feed = GenRSS(
    title='SmartFridge',
    site_url='https://example.com/',
    feed_url='https://example.com/rss.xml',
    image_url='https://example.com/image.jpg'
)
xml = feed.xml()
```
### Expected Behavior
<!-- Tell us what should happen. -->
returns xml like
```python
'<image>'
       '<url>https://example.com/image.jpg</url>'
       '<link>https://example.com</link>'
       '<title><![CDATA[title]]></title>'
'</image>'
``` 

### Actual Behavior
<!-- Tell us what happens instead. -->
Returns xml without image attribute without errors.

### Environment

* OS: Ubuntu 20.04.1 LTS (64 bit)
* Python version: 3.8
* GenRSS version: 1.0.5


Discussion:

Patch:
diff --git a/.gitignore b/.gitignore
index d9ecf51..361de9e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -152,4 +152,5 @@ tags
 
 # IDE
 .idea/
-.c9/
\ No newline at end of file
+.c9/
+.vscode/
\ No newline at end of file
diff --git a/genrss/__init__.py b/genrss/__init__.py
index 5dd3096..725cba3 100644
--- a/genrss/__init__.py
+++ b/genrss/__init__.py
@@ -100,7 +100,7 @@ class GenRSS:
         channel_image = self.image
         if not channel_image and self.image_url:
             channel_image = Image(self.image_url, self.site_url, self.title)
-        if isinstance(image, Image):
+        if isinstance(channel_image, Image):
             channel.append(channel_image.to_element())
 
         for category in self.categories:


Test patch:
diff --git a/tests/test_rss.py b/tests/test_rss.py
index d9c0eff..cbae47f 100644
--- a/tests/test_rss.py
+++ b/tests/test_rss.py
@@ -80,10 +80,15 @@ def test_feed_image_url():
     image_url = 'https://s3.smartfridge.me/image.jpg'
     feed = create_rss(image_url=image_url)
     xml = feed.xml()
+
     assert xml
-    assert (f'<image><url>{image_url}</url>'
+    assert (
+        '<image>'
+            f'<url>{image_url}</url>'
+            '<link>https://smartfridge.me/</link>'
             '<title><![CDATA[SmartFridge]]></title>'
-            '<link>https://smartfridge.me/</link></image>') in xml
+        '</image>'
+    ) in xml
 
 
 def test_feed_webmaster():