"Users may translate this field"

Once a content type is enabled for multilingual support with entity translation, it can be found under link: /admin/structure/types/manage/article/fields/field_image/field-settings (taking for example the core node type article with an image field)

Let us know (and mark the issue as active) if you didn't succeed in finding it.

That is odd. Would you mind sending a screenshot of your field settings page? The one at: http://www.example.com/admin/structure/types/manage/article/fields/field...

On another note, when you have created a field and then revisit the field settings page, it should present you with a big red warning: There is data for this field in the database. The field settings can no longer be changed.. This also applies to whether you can translate the field or not. In my experience, changing the translatabilty of a field once it has already been used, causes all sorts of problems that can then only be solved by manually adjusting values in the database.

I don't think I'm able to help you without more information. Do you have more than one language installed? Are there any relevant messages in the watchdog log? Have you already tried to make content with the new field? Can you post the content of your status report? What version of the modules do you have installed in your fresh install of 7.2?

In my setup I have no trouble finding the checkbox.

This is an old support request but to enable entity translation in an existing field, you have to go in "field settings" :

You can change that setting despite of the warning message. See : #1030972: Clarify that translatable setting can be changed in field settings form

Now the option to make fields translatable is under the edit tab.