How to clear browser cache when re-uploading image with same filename, in php?

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I have a listing of items, that also contains an image thumbnail. Sometimes I need to change the thumbnail image, but keep the filename the same. Is there a way to force the browser to download the newly uploaded image, instead of grabbing one from the browser cache?

This is very pertinent when people update their avatars, which causes confusion for some users, who keep seeing their old avatar, until they clear the browser cache, or restart the browser.

Append a unique number to the end of the image src



echo "<img src=../thumbnail.jpg?" . time() . ">";

do this only on the form for the updating avatar

works for me

btw, this works well for forcing updates of other static files

i.e. html for css files is

<link rel="Stylesheet" href="../css/cssfile.css?<?= md5_file('cssfile.css'); ?>" /> 

How to clear a browser cache when re-uploading an image with the , How you clear the cache depends on which browser you are using. I use Firefox Developer Edition. How do I clear a browser cache when re-uploading an image with the same filename in PHP? 1 Answer. Heidi Cool, Front End How do I redirect to a page from a login page using PHP? 20,199 Views � JavaScript: How� While you're clearing the browser cache you can also clear a few other items. Internet Explorer is present in every copy of Windows, even Windows 10. Even though Microsoft has been pushing it’s Edge browser very hard, many people prefer the familiarity of Internet Explorer.

You can use the modification time of file:


$filename = 'avatar.jpg';
$filemtime = filemtime($filename);

echo "<img src='".$filename."?".$filemtime."'>";

//result: <img src='avatar.jpg?1269538749'>


when the file is modified will clear the client cache

Cache Not Expiring When Overwriting an Image Via Upload � Issue , I have a system which allows uploading images to a media directory. image that uses the same file name, should the cache mechanism in ImageProcessor If any of those values are different then it will reprocess the image. In short, there's no way to force the browser to clear the cache from my end as� This whole procedure (must-revalidate, If-Modified-Since, 304 answer) will make it possible for the browser to cache the image content but at the same time ask your server if the file has changed. Another, maybe simpler, solution is to only set an Expires header a short time in the future , for example ten minutes, and inform the user of the

You can invalidate the cache for an entire page by altering the headers:

header("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1
header("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); // Date in the past

clearstatcache - Manual, time, cache, image, php. Resolved: How to clear browser cache when re- uploading image with same filename, in php? posted by admin on� 4. Close the browser and relaunch it. This is how to clear cache in Vivaldi browser. How to Clear Cache in Brave Browser. 1. Launch the Brave browser. 2. Click on the Menu icon available on the top menu bar (next to brave browser icon) and select Settings. 3. Next, on the left pane switch to the Security tab.

When sending out the image, make sure not to send any Expires header. Also consider sending this cache header:

Cache-Control: must-revalidate

This will make the browser ask your server for the image every time. Watch for an If-Modified-Since header in the request; if the image is not modified, answer with an 304 HTTP code.

This whole procedure (must-revalidate, If-Modified-Since, 304 answer) will make it possible for the browser to cache the image content but at the same time ask your server if the file has changed.

Another, maybe simpler, solution is to only set an Expires header a short time in the future, for example ten minutes, and inform the user of the ten minute delay. This will speed up most page loads since there's no need to do any HTTP request for the image at all.

Can PHP clear the browser cache and refresh?, For instance, if the same file is being checked multiple times within a single script, to call clearstatcache() if you are performing multiple operations on the same Clear the realpath and the stat cache for a specific filename only; only used if Note: This is separate from the caching typically done by browsers for all GET� The leverage browser caching warning in PageSpeed Insights means you need to add cache-control headers to those resources so that they cache properly. For example in Apache you can add this to your .htaccess file.

Cached images are also invalidated on manual page refresh (pressing F5 in browser). This can be simulated with Javascript method location.reload() being fired on body load. To avoid perpetual reloading, this may take place only once. When the user uploads a new avatar, the ReloadPending request is set persistently in his/her session and it is reset when it's been answered.

if ($session['ReloadPending']) 
{   $session['ReloadPending']=false; 
       echo "<body onload='location.reload(true);'>"; 
} else echo "<body>";

Reloading the whole page after avatar upload will cause the page flicker but this happens only once, which, I believe, is acceptable.

PHP clearstatcache() Function, Since this replaces an earlier image, it gets given the same name (desirably). I have a script which allows a visitor to the web site to upload an image. Clearing the browser cache and refreshing the screen (manually) shows loaded is to append a unique query string to the filename of the <img>'s src. I made some changes to my website and people were not seeing the change. Then the thought came that they need to clear their cache. I helped a few people do that and it solved the problem. But how

I've replaced an existing image with a new one, but my website still , Output file size, truncate file, clear cache, and then output file size again: <?php // output filesize echo filesize("test.txt"); echo "<br />"; $file = fopen("test.txt", "a+"); In the simplest terms, a browser cache is a place on your local storage drive where your browser will save files from websites you visit for the purpose of faster loading, if you visit that same website again.

Programmatically Uploading Images, Videos, and Other Files , If you're using a different method to generate your URLs, you may need to For more information about CDN invalidations, please see the upload API documentation Is there no way to manually clear cache or at least reduce that wait time to a The image is still the same, the tags are still the same too. Strictly speaking, you can’t actually clear someone’s cache. (It’s their cache, maybe they want it around for some reason.) If your goal is to prevent some request from coming from their cache, some people use the cache-control, expires, and pragma no-cache solution that Gayathri gave which is fine.

How to force a browser cache refresh after upda, Learn how to upload images, videos, and other files with only a line or two of uploading media files from server-side code, directly from the browser or from a Add an empty file to your bucket with your cloud name as the filename, under or if you are uploading multiple files of different asset types with the same settings .

  • Note that calculating md5 takes a lot of processing power. It would be better to use filemtime().
  • Not possible in many cases due to cached nature of HTML code.
  • can tell me which cases?
  • Where a cache generated HTML code into the DB, which gets updated once every few days
  • This is awesome should have thought of this +1
  • This will unfortunately make caching of the file impossible, increasing the page load time and bandwidth cost.
  • Then only do it after an upload?
  • Can we do this only with ONE image, and not entirelly application?
  • What do you mean by "when sending out the image"? After I upload an image, and use header("Location:whatever.php"); ?
  • No, I mean when someone requests the image file, i.e. does an HTTP request for /example/image.jpg
  • Nope, didn't worked using Google Chrome. UPDATE: page was in cache, it worked! Thanks!