apex:image on visualforce page not updating on page reload when user updates the image document it uses

Question

When a user uploads an image on my Visualforce page, it correctly adds or updates the document in a document folder in Salesforce. When the document is added or removed, if I refresh the page, the change is displayed immediately. However, if I just change the picture, the change does not take effect for a while... I assume this may be some caching issue with salesforce? But setting cache="false" on my page did not do anything.

Is there a way to reflect the changes of document bodies immediately? (When document is updated, everything but the MIME type and body are the same, including name). Or is my a valid option to delete that document and re-insert it when the user 'updates' the image instead of just trying to update the content of the document?

I am also grabbing the image url on load in a variable getter in my controller like: '/servlet/servlet.FileDownload?file=' + emailLogoDoc[0].Id;

I am not sure if there is some setting I can set to stop the caching so it grabs what is actually in the document on every reload/query, or if it is the way I am getting the image Url that is the problem.

Answer 1

I'm not 100% on this, but it seems to me you should be using URLFOR for this purpose instead of using hard-coded URLs:

<apex:image value="{!URLFOR($Action.Document.Download, logoDoc.Id)}" />

This presumes that the variable that holds the information is an object called logoDoc and the Id is Id; adjust these parameters as necessary. Using URLFOR should cause Salesforce to generate a URL that should refresh immediately the next time the page is rendered (i.e. immediately).