First of all I'm not sure if this is the correct place to post this question, if its not please tell where should I post it.
My doubt is if I can use Dropbox to host images and then send emails linking that image to preview it , I don't want to send it as an attachment , but as an image in the email , is that possible ? Or do I have to upload it to a hosting?
This question was already replied here and I strongly agree with the accepted response: don't do it in production.
Dropbox imposes limits on bandwidth that you can confirm here and stated below, so I would say it's ok for internal testing only.
Dropbox Basic (free) accounts:
The total amount of traffic that all of your links and file requests together can generate without getting banned is 20 GB per day. The total number of downloads that all of your links together can generate is 100,000 downloads per day.
If you don't have other option or still insist on doing it, just be sure you keep yourself under the limits in order to don't go against their terms of use and avoid being banned.
