Every message loads twice

[Vaelek]

Using in Firefox with Gmail, every message loads twice, slow enough that I see the text load, then the images, then it all blinks away and does it a second time. After initially viewing it, clicking to another message and coming back loads only 1 time.

[trockerapp]

Thanks for reporting this issue. At the moment, this doesn't seem to happen for us (perhaps we are being served different versions of Gmail right now) but it is a familiar behavior that we have sometimes encountered before. Basically, it seems that sometimes Gmail resets all image urls in an email moments after the email is loaded. This would cause a second loading of images because Trocker needs to whitelist them again.

To clarify further, Trocker blocks all images in Gmail/outlook by default (link to code) and then checks each of them and whitelists the ones that are not too tiny to be a tracker (link to code). This is because we don't want trackers to have any chance to load before we have checked their image size. Now if Gmail resets the url of the whitelisted images to the original ones they would be blocked again until Trocker whitelists them again.

Since, Trocker has no control over this Gmail reloading behavior, it may not be possible to completely stop it from happening. Moreover, it seems to not be present in all Gmail versions. At the very least, perhaps we could reduce the annoyance by making Trocker recheck images faster (only temporarily after a new email is loaded in order to avoid a performance burden).

Feel free to chime in if you have any suggestions or any other observations.

[gingerlime]

not sure if this helps, but I also bumped into this. I'm using GSuite business with Trocker on Firefox/Mac.

Here's a short screen recording. I had to mask some of the data, but I hope it still shows the behaviour... Images appear/disappear a couple of times. From my experience this only happens the first time I open a new message. If I re-open an older message then it works ok.

Note that the animated gif cycles by default, so it's a bit hard to see, so I also attached a zip file with an mp4

mailchimp trocker.zip