Is there a means that allows members to upload images in posts, but to prevent those images from being downloaded by other members?
Thanks kindly,
Ross
What’s the use case?
Could they make the posts PMs?
We are a camera club and take intellectual property seriously. We invite our members to share images, either simply for pleasure or for coaching. We would prefer that even though the site is private and the only way to join is by invitation, to prevent members from right clicking on an image in a post and downloading it to their computers.
Because we want all members to see the postings, PMs don’t fit the requirements.
What’s to stop anyone from pressing the screenshot button on their device to copy the photos?
That said, although it is a bit of protection theater more than real protection, I am not opposed to a theme component here which disables the right click action on images cc @Johani
Hey Jeff, excellent point. The difference between a downloaded image and a screenshot is going to be related to size and resolution. Our members will be posting larger images at higher resolution with the EXIF data intact. A screenshot will surely grab the image, but only at web screen resolution which is never going to make a decent print. Downloading the member’s image could provide a print ready image and even though I trust our members (it’s in our terms and conditions about using the work of others), some of my early adopter group are asking the question. Cheers!
If the user is tech-savvy, there is literally no way to stop them from downloading the image via their browser controls, to be clear. So you’d only be “stopping” people who were casual computer users.
If someone can see the image in their web browser there is nothing that can stop them from saving the image locally.
Photographers need to know that. If they want to protect their images, they should do it with watermarks. If you really want to protect them you could have a plugin developed that would watermark all images with the forum name and maybe the username too.
Unless the photographers transfer the rights to the forum they need to take responsibility to watermark their images prior to uploading. Otherwise when said watermarking is defeated it’s easy to shift blame onto the site owners.
And why would you let them do that if no one is supposed to see that data? Either put in place a file-size limit that forces the user to web-optimize before uploading, or have a background task run through uploads, and process them to web specs. Keep only the webified files.
If you don’t want anyone to save the full-size file, you don’t want the overhead of having it loaded for everyone who views the forum thread either.
Thank you all for the input. Discourse is working as needed for our club. If there is no native method to prevent users from downloading images that other users post I will update our terms of use policy.
This topic can now be closed.
您好，能否为某个主题下的缩略图或所有图片添加水印功能？
谢谢！
水印对于销售照片非常有用。
但无法对带有水印的照片进行评判。
我们在论坛中展示照片是为了获取意见和改进建议。如果照片带有水印，会干扰图像的查看。
虽然无法阻止技术熟练的用户从屏幕截取副本，但尽量增加难度总是更好的。
我认为上述说法完全站不住脚。水印正是大多数代理机构和摄影工作室在向客户展示样片、出售复制权或订购打印服务时采用的方式。
如果水印真的妨碍了客户做出选择或导致销量下降，他们早就改用其他方法，例如 RMS（无水印样片）了。
当然，我说过：水印是销售图片的最佳方式。
但我们并不是在销售图片，我们是一个摄影论坛，我们展示图片是为了获得他人的意见和批评。
你不会在任何艺术画廊中看到作品被加上水印展出。
你也不会发现任何比赛评审团会接受带有水印的参赛图片。
无论如何，如果你将带水印的图片上传到摄影论坛以寻求意见，你收到的反馈只会是“水印破坏了图片”、“我无法在水印存在的情况下判断图片质量”或“水印太分散注意力”。
即使只是图片上过于明显的签名，也会收到类似的反馈。
因此，水印对我们来说不是一个可行的选择。
它或许是一种保护图片的优秀方式（但如果水印不够牢固，效果就不太好；透明的水印很容易被移除，角落里的水印也很容易被删除）。
这似乎是一个合理的解决方案？
调整大小或重新压缩，使其在满足访客和社区成员的网络体验的同时，不必达到印刷质量？
稍等一下……
“最大图片兆像素”这一站点设置现在不是已经 100% 解决了原帖的问题吗？
如果你不希望有人盗用图片进行打印，只需将这里的兆像素值调低到无法打印的程度即可。将其降至 2 兆像素，图片在网络上的显示效果仍然“尚可”，但完全无法用于打印。
这取决于您如何定义网络上的“可用”。
对我们来说，长边小于 1900 像素的图片在判断图像质量时显得不足。
您假设人们会盗用照片用于打印，但通常并非如此。
大多数情况下，照片被用于博客，甚至报纸或新闻频道。
保护照片最有效的方法是使用清晰可见的水印，并覆盖照片的大部分区域。
但这并不是摄影论坛的解决方案。
让下载照片变得更困难并非根本解决办法，但有一定帮助。
所给代码的问题在于它阻止了在所有地方使用鼠标右键。如果能仅在点击图像时阻止右键操作，那就太好了。
这是一个边缘情况。若要保护图片免受下载，你需要将图片存储在一个专门为此设计的服务器上，例如允许 Discourse 访问低质量图片用于讨论，而获取完整图片则需要点击跳转到另一个网站（该网站可能使用 Discourse 作为单点登录服务器），这样或许能在一定程度上防止用户下载图片。即使对于专用的 Web 应用来说，这也是一个难以实现的任务。
如果你确实是在寻找这个功能，我认为最好的下一步是在 Marketplace 上定制一个插件。
我们不需要专用服务器，也不需要特殊的图像处理。事实上，我们更倾向于服务器完全不处理图像，因为摄影师的职责是按照自己的喜好准备图像。
我们已经运营了17年，从未需要这些功能。
由用户自行决定要上传的图像尺寸，并承担可能被盗用的风险。
我们只是希望让图像下载不那么明显，就像 Flickr、500px 和其他图片分享网站所做的那样。