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Watermarks - How to Guide and Questions

darkufo Member
in General support
Hi,

I wondered if there was a guide or walkthrough document about how watermarking works.

Here are some questions I have about watermarking.

1) Are watermarks actually added to the image so that when someone saves them they get their image has our watermark on them?

2) Are watermarks applied still if we upload via FTP. If so how does that work?

3) If we turn on Watermarking what happens to existing images that have previously been uploaded before we turned on Watermarking

4) Can we use "text" to add as a watermark or are graphics only supported.

Many thanks in advance for help help you can provide.

Comments

  • acrylian Administrator, Developer
    1) Yes. Watermarks are added to the image itself by the image processor when resized by Zenphoto and cached. That is for all images except the full images you upload. Those only on request by setting the options.
    2) Yes, see #1
    3) As they are cached nothing happens unless you clear the cache so the cached images are regenerated.
    4) Only images supported (as there is no option, right?) but of course you can use text as an image...
  • darkufo Member
    Awesome, thank you so much indeed.
  • darkufo Member
    Thanks again Acrylian.

    I've enabled watermarks and it works a treat, really good. I've enabled it for Images and Full Sized Images

    However, if someone users a bulk image downloader such as BID etc it downloads the raw original file (without the logo)

    Is there anyway to prevent this?
  • acrylian Administrator, Developer
    You mean directly from the /albums folder? Then Zenphoto is not involved and you need to protect the /albums folder eitehr with proper permissions or with an .htacceess file (there is one on the troubleshooting).

    Alternatively you can move your albums folder outside the webroot (see the config file). Drawback will be that multimedia items then will not work anymore.

    Btw, I made a troubleshooting entry out of your questions.
  • darkufo Member
    Thanks once again acrylian, very helpful.

    Do you have a link to the Troubleshooting page with the htaccess. I could not find it.
  • darkufo Member
    It's ok I found it :)
  • darkufo Member
    Acrylian, sorry to bother you again.

    Ok, I added the .htaccess

    ----
    <IfModule mod_rewrite.c>
    RewriteEngine On

    # It is actually recommended to allow blank referers as some personal firewalls or anti virus tools clear the referrer.
    # Uncomment the following line if you want to allow them.
    #RewriteCond %{HTTP_REFERER} !^$

    # Enter your domain here. Add more lines like this to allow more domains
    # If you are using Zenphoto in a subdomain write subdomain.yourdomain.com instead (www\.)?yourdomain.com
    RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?spoilertv.co.uk [NC]

    # Protect your full images in the albums folder
    RewriteRule \.(jpg|jpeg|png|gif|flv|mp4|mov|3gp)$ - [NC,F,L]

    </IfModule>
    ---

    Now when I go to my browser and for example go to this full size and unwatermarked image

    http://spoilertv.co.uk/images/albums/alphas/season-1/cast-promotional-photos/nup_144681_0003.jpg

    I get redirected to my homepage (spoiletv.com)

    This is great I thought.

    However, when I run Bulk Image Download it still manages to download the full image.

    Not sure how/why it is able to.
  • darkufo Member
    In the log files I'm seeing this

    Date: Mar 07 08:58:53
    HTTP Code: 200
    HTTP Version: HTTP/1.1
    Referer: http://spoilertv.co.uk/images/archer/season-3/Promotional
    Size (in bytes): 52528
    User Agent: Episode Photos/Episode 3.01 - The Man From Jupiter/Screenshot2011-11-30at3.43.34PMcopy.jpg.php Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)

    It looks like it's using our referrer which would explain how it's bypassing it.

    Any way to avoid this?

    Could I simply block all referrers? What impact would this have? We don't have any need for the full image to be displayed. Would it interfere with Zenphoto from generating the watermarked and cached images?
  • acrylian Administrator, Developer
    I don't know that tool you are using. What is that a desktop applicate, browser based or on your server?
  • darkufo Member
    It's tool called NeoDownloader used for BulkDownloading.

    It's a Windows Desktop app but it appears to run an instance of IE as a process. So I guess it's actually "visiting" the site in the background and getting the image hence it circumnavigates the referrer check.
  • acrylian Administrator, Developer
    I have no idea right now. There is also another way to block via .htaccess using deny: all. Don't have the exact syntax right now at hand. But maybe the best is to move the albums folder out of the accessible web root.
  • darkufo Member
    Thanks Acrylian.

    I'm a bit loathed to try that at the moment as we have 100GB of images and over 100,000 images on the site.

    Whenever you get time if you could find the htaccess syntax I think that would be better for us.

    No rush and appreciate your time so far, it's much appreciated.
  • acrylian Administrator, Developer
    I meant something like this (quickly searched):
    http://www.kavoir.com/2009/01/htaccess-deny-from-all-restrict-directory-access.html

    here is a quick tool to generate htaccess files:
    http://www.htaccesstools.com/hotlink-protection/
  • darkufo Member
    Ha, that was easy.

    I just added deny from all and it seems to work.

    Not noticed any implications yet.
  • tunafish Member
    Thanks for the tip!

    Here is a page with some very usefull .htaccess examples:
    http://www.htpasswdgenerator.com/apache/htaccess.html
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