We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Can't submit new team after changing image.
Can't believe this didn't come up yet. I noticed this while exploring [create.json.spt](https://github.com/gratipay/gratipay.com/blob/master/www/teams/create.json.spt) which inspires the new [edit.json.spt](https://github.com/gratipay/gratipay.com/pull/3923/files#diff-6). 

The way it is written right now, we first write the team details to the db (with a unique generated `slug`) and _then_ try to save the team image. If a user uploads an image of size  > 1Mb or an image which is not a jpg or png, the team creation won't be successful as far as the user is concerned and he'll resubmit the team application form with an appropriate image. But when he does again, we would have already created a slug for that team name resulting in a misleading message of `Sorry, there is already a team using <slug>.` when in fact the `slug` was created because we wrote the team details to the db first.


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `gratipay/utils/images.py`
Content:
```
1 import zipfile
2 from cStringIO import StringIO
3 
4 import requests
5 
6 def imgize(image, image_type):
7     large = None
8     small = None
9     crops = requests.post( 'http://gip.rocks/v1',
10                            data=image,
11                            headers={'Content-Type': image_type}
12             )
13     if crops.status_code == 200:
14         zf = zipfile.ZipFile(StringIO(crops.content))
15         large = zf.open('160').read()
16         small = zf.open('48').read()
17 
18     return crops.status_code, large, small
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/gratipay/utils/images.py b/gratipay/utils/images.py
--- a/gratipay/utils/images.py
+++ b/gratipay/utils/images.py
@@ -8,11 +8,22 @@
     small = None
     crops = requests.post( 'http://gip.rocks/v1',
                            data=image,
-                           headers={'Content-Type': image_type}
-            )
+                           headers={'Content-Type': image_type})
+
     if crops.status_code == 200:
         zf = zipfile.ZipFile(StringIO(crops.content))
         large = zf.open('160').read()
         small = zf.open('48').read()
+        return large, small
+    elif crops.status_code == 413:
+        raise ImageTooLarge
+    elif crops.status_code == 415:
+        raise InvalidImageType
+    else:
+        raise UnknownImageError
+
+class ImageTooLarge(Exception): pass
+
+class InvalidImageType(Exception): pass
 
-    return crops.status_code, large, small
\ No newline at end of file
+class UnknownImageError(Exception): pass

{"golden_diff": "diff --git a/gratipay/utils/images.py b/gratipay/utils/images.py\n--- a/gratipay/utils/images.py\n+++ b/gratipay/utils/images.py\n@@ -8,11 +8,22 @@\n     small = None\n     crops = requests.post( 'http://gip.rocks/v1',\n                            data=image,\n-                           headers={'Content-Type': image_type}\n-            )\n+                           headers={'Content-Type': image_type})\n+\n     if crops.status_code == 200:\n         zf = zipfile.ZipFile(StringIO(crops.content))\n         large = zf.open('160').read()\n         small = zf.open('48').read()\n+        return large, small\n+    elif crops.status_code == 413:\n+        raise ImageTooLarge\n+    elif crops.status_code == 415:\n+        raise InvalidImageType\n+    else:\n+        raise UnknownImageError\n+\n+class ImageTooLarge(Exception): pass\n+\n+class InvalidImageType(Exception): pass\n \n-    return crops.status_code, large, small\n\\ No newline at end of file\n+class UnknownImageError(Exception): pass\n", "issue": "Can't submit new team after changing image.\nCan't believe this didn't come up yet. I noticed this while exploring [create.json.spt](https://github.com/gratipay/gratipay.com/blob/master/www/teams/create.json.spt) which inspires the new [edit.json.spt](https://github.com/gratipay/gratipay.com/pull/3923/files#diff-6). \n\nThe way it is written right now, we first write the team details to the db (with a unique generated `slug`) and _then_ try to save the team image. If a user uploads an image of size  > 1Mb or an image which is not a jpg or png, the team creation won't be successful as far as the user is concerned and he'll resubmit the team application form with an appropriate image. But when he does again, we would have already created a slug for that team name resulting in a misleading message of `Sorry, there is already a team using <slug>.` when in fact the `slug` was created because we wrote the team details to the db first.\n\n", "before_files": [{"content": "import zipfile\nfrom cStringIO import StringIO\n\nimport requests\n\ndef imgize(image, image_type):\n    large = None\n    small = None\n    crops = requests.post( 'http://gip.rocks/v1',\n                           data=image,\n                           headers={'Content-Type': image_type}\n            )\n    if crops.status_code == 200:\n        zf = zipfile.ZipFile(StringIO(crops.content))\n        large = zf.open('160').read()\n        small = zf.open('48').read()\n\n    return crops.status_code, large, small", "path": "gratipay/utils/images.py"}], "after_files": [{"content": "import zipfile\nfrom cStringIO import StringIO\n\nimport requests\n\ndef imgize(image, image_type):\n    large = None\n    small = None\n    crops = requests.post( 'http://gip.rocks/v1',\n                           data=image,\n                           headers={'Content-Type': image_type})\n\n    if crops.status_code == 200:\n        zf = zipfile.ZipFile(StringIO(crops.content))\n        large = zf.open('160').read()\n        small = zf.open('48').read()\n        return large, small\n    elif crops.status_code == 413:\n        raise ImageTooLarge\n    elif crops.status_code == 415:\n        raise InvalidImageType\n    else:\n        raise UnknownImageError\n\nclass ImageTooLarge(Exception): pass\n\nclass InvalidImageType(Exception): pass\n\nclass UnknownImageError(Exception): pass\n", "path": "gratipay/utils/images.py"}]}