Is it possible to add visible/invisible watermark to photos already uploaded to Picasa Web/500px/Flickr?

Do they preserve EXIF(metadata) of the image?

I am looking for free tools/services. If downloading software is required, I would prefer Linux/Ubuntu.

Update: In the light of two answers already given; adding a clarification. A solution that lets adding the watermark without downloading the photos from the respective locations is asked for.

  • \$\begingroup\$ Downvoting without comment isn't helpful just rude \$\endgroup\$
    – user9817
    Aug 20, 2012 at 8:27
  • \$\begingroup\$ @ClaraOnager Sorry I don't get you. I can't even upvote!! \$\endgroup\$ Aug 20, 2012 at 11:30
  • \$\begingroup\$ Not you, someone else downvoted for no apparent reason \$\endgroup\$
    – user9817
    Aug 20, 2012 at 12:51
  • \$\begingroup\$ What are you trying to do here? I have to admit, I can see why it was down voted as the question, given the way it was worded, would imply a less-than-savoury need here. \$\endgroup\$
    – Joanne C
    Aug 21, 2012 at 3:09
  • \$\begingroup\$ JoanneC: Sorry, may I know what is wrong in the question? Does it sound something else? If so, please help in re-phrasing it. \$\endgroup\$ Aug 21, 2012 at 4:09

2 Answers 2


Ok. I am not sure what you are asking, but I can try to guess.

If a photo is already uploaded, it is rather difficult to modify, as that copy is no longer on your computer.

I suggest downloading the photo, applying the watermark in photoshop/gimp (A free, open source version of photoshop), and re-uploading. I am not sure if this will preserve the metadata though.

As to how to apply a watermark in gimp, that is another question entirely.

  • \$\begingroup\$ @Stephan Thanks, I am looking for a solution that might let me do it without downloading them. \$\endgroup\$ Aug 24, 2012 at 16:05
  • \$\begingroup\$ I am accepting your answer, as there may not be a better answer than this one. \$\endgroup\$ Aug 28, 2012 at 16:25

I will provide all who visit this page with a working answer, having in mind that this is now 2015:

Of course you can have you images uploaded to a Google+ album and still have you originals on your computer. Supposing you have uploaded the images with Picasa 3 and you still have the connection in Picasa with both the local and online album.

What you need to do to ad a watermark, change a watermark or remove a watermark from any already uploaded images is to have Picasa overwrite the online images with a fresh copy. One way of doing that on a PC is:

Set up Picasa to ad whatever watermark you want or have to set no watermark at all.

Select all images in the local album, Press Ctrl + R (turn all of them 90 deg right), let Picasa sync everthing in the album, then press Ctrl+Shift+R (turn them back again), and then let Picasa sync everthing again.

All images in the online album will now be updated with any new watermark settings you applied before the procedure.


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