Gmail's new image caching is breaking image links in newsletter
I think I have figured out the GoogleImageProxy issue.
This is something related to CACHING concept. suppose, you have recently deployed your php code on your server but you forgot to upload images. you tested once with your email logic. your system generated an HTML email. When this email will hit the gmail server GoogleImageProxy will try to fetch and store the images from your site to its own proxy server. while fetching the images, GoogleImageProxy found some 404 statuses against your missing images and 403 against some protected images. GoogleImagesProxy has stored these statuses into its own proxy server.
Now tried to open your email, you noticed some 404 statuses against your images. This is something understandable. You immediately realized that you forgot to upload some images, so you uploaded them to your server. and also you have fixed some permissions against protected images.
You are all done now. Now you try to run your php-email script once again. As a result you receive another email in your Gmail or Hotmail inbox. you had fixed all the issues with your images. Now the images must be displayed in your email content. but you are still unable to see the images.
Ah, possibly you forgot to clear your browser's cache. Clear your browser's cache and load the gmail or hotmail page once again. But the result will be still the same. Try to apply dozens of fixes/patches and try to run your php-email script a thousands time. But the result will be still the same. No improvement.
THE REAL PROBLEM
What the hell is going on? Let me explain it to you. Go to your access log and try to find requests from GoogleImageProxy. You'll be surprised to see that there will be only 2 or 3 three requests from GoogleImageProxy depending on the number of different images used in your email. GoogleImageProxy never tried to fetch images Even after you have fixed the issues with your images by uploading missing images and setting permissions for protected images. Why? Clearing your browser's cache has no impact. GoogleImageProxy will never fetch the fresh images even for your newer email because the images are now cached into GoogleImageProxy along with their last status code and not cached in your own browser's.
GoogleImageProxy has set its own expiry date for the images. I think one month. so now the fresh copy of images will be fetch after expiry date. I mean after one month. You can not force GoogleImageProxy to fetch the images. But its important for you to display images in your email. What can be the solution?
THE SOLUTION
Following is the only way to force GoogleImageProxy to fetch your images
- Rename your images to something else with png, jpg or gif extensions only.
- Don't use any kind of query string in your image url like
?t=34343 - your image must include png, jpg or gif as an extension.
- your image url must be mapped onto your image directly.
- If you need to use some proxy url for your protected images then your response must include the proper header like
Content-Type: image/jpeg - File extension and content-type header must match
- Status-code must be 200 instead of 403, 500 etc
IMPORTANT NOTE
Try to repeat the whole process for every run of php-email script. because every time GoogleImageProxy will cache your images and you'll have to repeat the same process for every new try.
Hopefully this will fix the issue for most of the people.
Based on your example, it looks like you are using traditional extensions (.jpg, .png, .gif). Some folks on this thread, describing the same issues you are facing, have stated that using those extensions solves the problem.
Other possible solutions:
- Image links broken in Gmail because of google's Image proxy
- Doubtful, but maybe a cookie problem
- Image URL proxy whitelist setting - this has turned out to be the solution for a few users who are under Google Apps. Via Gmail is not showing image when image url is getting appended with https://ci4.googleusercontent.com/proxy
I was having a similar issue, but it was caused by the length of the URL. Google generates the following URL when caching an image from gmail:
https://ci4.googleusercontent.com/proxy/[hash]#[url])
The hash generated is based on the URL of the image, but the size will vary based on characters used. I ran several tests with different sized URLs, and found the cached image would fail to load consistently (400/Invalid Request) if the hash exceeds 2076 characters in length (close to 2048 bytes + meta? not sure).
Again, the image URL could generate a hash that exceeds this many characters at ~1000 special characters, or 1500+ simple characters. If the hash exceeds 2076 characters in length, the request fails.
I realize this is an old post, but hopefully this helps other devs scouring Google