Slow website due to Image-Requests from sended Newsletters?

[update AG]

Our Customer has this Workflow to create and send newsletters.

1. Create the Newsletter in Processwire as a Page.
2. Copy/Paste the generated HTML to Cleverreach (for sending the E-Mails) and send the NL to the users.

Now the thing is, that our Customer has send out a NL with 100k recipients on last friday at 16:00 pm and then the website was very slow or event not reachable for 2 hours.
When I look at Cleverreach there were 30k Openings of the NL until now. Since the last NL had like 15 Images this would probably lead to 450k Web Requests for Images which probably is to much traffic for the webserver to handle.

I did some research and it looks like that perhaps hosting all the NL images on a CDN is the way to go? Has anyone experience with this in conjunction with Processwire?

An alternative would also be to use the image-editing capabilities of Cleverreach where they probably would need to upload the images there and then adjust the NL-HTML accordingly but I think this would be too cumbersome when they instead just use the processwire page editor like they do at the moment.

KR
Orkun

[millipedia]

One fairly simple thing to do (if you have access to the domain name) would be to use Cloudflare to proxy the site. The free tier includes their CDN which is going to help enormously and means you don't have to worry about integrating a CDN with your website.

You should also make sure that the images that are getting requested have been suitably resized. You don't want to be serving large images to users checking their email on a phone.

Also - your webserver should be able to handle 450K requests anyway. Especially given that Gmail etc will cache your newsletter images, and that many email clients won't even load remote images, I'd check that that the problem really is too many requests coming in and not something else. If it is a problem with the server being overloaded then you should probably look at different hosting.