We are using a png/8 sprite on a client's website. He is reporting the image is appearing distorted for him and on other computers on the company.
Here's how it should look:
http://i.imgur.com/wfV7ReR.jpg
And here is the print screen the client sent us:
http://i.imgur.com/sWKDYKU.jpg
I have tried donloading and exporting it again, uploading again. The problem is: On our computers it looks fine, so it's hard to test it. Our client is viewing it in IE: 11 and Google chrome: 41.0.272.118.
Has anyone seen this type of error before?
It may be the device-pixel-ratio is better than 160dpi; that'd throw off some CSS used for spriting.
If this shows "1" for you and a different value for them, I'd dig farther on that one. You could probably test this by hitting the site with an iPhone or newer Android device; they have >1.0 pixel ratios.
http://www.devicepixelratio.com/
Edit: this would also show up across-browsers on their end, as it's tied to the hardware, and not IE11.
My bet in that case is the PNG is somehow broken.
graphicdesign.stackexchange.com might be more useful; I don't know if this is fixable in CSS. (Might be; look for hacks around image backgrounds as well.)
Looking around, if you have Photoshop, you might try saving the original image, then creating a copy and changing this setting:
Image -> Mode -> Check "RGB Color"
Alternatively, try opening the image in pixlr.com, change anything however slightly, then save and use that one.
My strong suspicion is something in the way the PNG/8 is saved (maybe the alpha channel) is the issue, not any CSS you've written. Good luck!
We are using the og:image property to supply facebook with the correct image, but in some instances it get's more images which it parses from the DOM. eg:
http://www.facebook.com/sharer/sharer.php?u=http%3A%2F%2Ffunda.nl%2Fkoop%2Futrecht%2Fappartement-48611144-breedstraat-122%2F&t=Woning+te+koop%3A+Breedstraat+122%2C+Utrecht
Only the first image should be shown there. If you look in the debugger it looks fine:
http://developers.facebook.com/tools/debug/og/object?q=http%3A%2F%2Fwww.funda.nl%2Fkoop%2Futrecht%2Fappartement-48611144-breedstraat-122%2F
Anyone knows whats going on here?
I've just encountered this issue in a site I maintain.
It appears that bloody Facebook changed again things without notifying anything to developers..
Image for og:image must be now at least 200x200px.
If it is smaller, than facebook will take other images that it parses from the same URL, even if these images have nothing to do as leading image for that URL.
Just take care that og:image is big enough and it will be ok.
* Notice that even after you change it, it may appear wrong for some time, if the URL is already cached in FB. To solve it immediately, just pass again the URL to the FB debugger.
i have problems to obtain good thumb from some images, when the original images are striped or checked shirt.
With the magento's gd2 library resize() in Varien_Image_Adapter_Gd2 class (magento 1.5 version) i obtain an image with a strange effect that modify the aspect of real image.
I can't find the name of this effect, so i can't search this issue on google! :(
You can see my issue in these 2 images:
As you can see, on the thumb image there are some rolling strange lines in particular in top-left position.
The issue is more evident on checked shirt, so i have to find a solution to correct this.
If anyone have some tips on this issue, please said me! :)
thx
Luca
'Moire' is the pattern you describe and it is particularly visible due to use of 'gd2' library which may or may not use bicubic scaling.
I am not sure that #Guerra has understood the problem here, but, to me, it is a straightforward lack of bicubic (or better) scaling.
See the answer on this question and follow the link:
https://stackoverflow.com/a/255666/1617149
So you may want to scale your images for the frontend using imagemagick instead of the standard gd2 library that comes with Magento and use a filter.
You can run imagemagick through php (the proper way), or, if you have complicated image processing on the go, you can go commandline 'exec' and prototype your image processing that way. I don't have any ready-to-roll code for that, however, that is what you need: better thumbnail rendering than you get with gd2.
Try use cloudzoom, he autosize your images to fit on your needs.
http://ecommerce-team.com/cloud-zoom.html
http://moztw.org/images/product-front-thunderbird.png
I am sure that this is a PNG image in RGB colors and a alpha channel (look at the shadow below the icon), but this file mysteriously works with IE6 w/o any special CSS hack (though it seems the alpha channel is being replaced by 2-bit mask in IE6).
Can anyone tell me exactly what information is in the file? It would be even better if someone could give a guidance on how to create such file. Thanks.
Edit: Friends at moztw.org added script hack to the website, so the above statement is no longer verifiable. But your are still welcome to investigate the image format.
That's PNG8+alpha. Explanation and examples in "PNG that works" article.
You can generate such files with pngquant (on a Mac, ImageAlpha is a GUI for it).
What are some effective strategies for preventing the use of my proprietary images?
I'm talking about saving them, direct linking to them etc...
Presently I have a watermark on the image, but I'd rather not.
.NET platform preferred, but if there's a strategy that's on another platform that integrates with my existing application that'd be a bonus.
It's not possible to make it "impossible" to download. When a user visits your site you're sending them the pictures. The user will have a copy of that image in the browsers cache and he'd be able to access it even after he leaves the site ( depending on the browser, of course ). Your only real option is to watermark them :O
You could embed each image inside of a flash application, then the browser wouldn't know how to 'save' the image and wouldn't store the raw jpg in the cache folder either. They could still just press the print screen key to get a copy of the image, but it would probably be enough to stop most visitors.
Response.WriteBinary(), embedded flash, JavaScript hacks, hidden divs.
Over the years I have seen and tried every possible way to secure an image and I have come to one conclusion: If it can be seen online; it can be taken, my friend.
So, what you really should consider what the final goal of this action would really be. Prevent piracy? If a gross and oversized watermark is not your style, you can always embed hidden data (Apress had an article that looked promising on digital steganography) in images to identify them as your own later. You might only offer reduced or lower quality images.
Flickr takes the approach of placing a transparent gif layer on top of the image so if you are not logged in and right click you get their ever awesome spaceball.gif. But nothing can prevent a screenshot other than, well, just not offering the picture.
If the music industry could get you to listen to all of your music without copying or owning files they would. If television could broadcast and be certain nobody could store a copy of the cast, they probably would as well. It's the unfortunate part of sharing media with the public. The really good question here is how you can protect your material WITHOUT getting in the way of respectable users from consuming your images. Put on too much protection and nobody will go to your site/use your software (Personally if you try to disable my mouse I'll go from good user to bad nearly instantly).
using JavaScript to override the click event is the most common I have seen...
see: http://pubs.logicalexpressions.com/pub0009/LPMArticle.asp?ID=41
I figure I might as well put in my two cents.
None of the above methods will work with perhaps the exception of a watermark.
Wherever I go, I can hit print screen on my computer and paste into a graphics editor, and with a little cropping, I have your image.
The only way to overcome the watermark issue would be to use photoshop tools to remove the watermark. At this point, i think most people would just give up and pay you for your content or at a minimum go rip off somebody else.
Short answer: you can't. Whatever you display to a user is going to be available to them. You can watermark it, blur it, or offer a low-res version of it, but the bottom line is that whatever images are displayed in the user's browser are going to be available to them in some way.
It's just not possible. There is always the PrintScreen button.
Whatever is displayed, can be captured.
I would watermark them, and reduce the resolution, of the actual files, instead of doing it through an application on the user's end.
unfortunately you can always screen grab the browser and crop the image out, not perfect but it circumvents almost every solution posted here :(
Another approach I've seen that's still entirely vulnerable to screen grabs but does make right-click and cache searching sufficiently annoying is to break the image up into many little images and display them on your page tiled together to appear as though they were a single image. But as everyone has said, if they can see it, they can grab it.
Realistically you can't, unless you don't want them to see it in the first place. You could use some javascript to catch the right mouse button click, but that's really about it.
Another thought, you could possibly embed it in flash, but again, they could just take a screenshot.
Sorry. That's impossible. All you can do is make it inconvenient a la flickr.
It's just not possible. There is always the PrintScreen button.
I remember testing ImageFreeze years ago. It used a Java applet to fetch and display images. The image data and connection was encrypted and the unencrypted image wasn't stored in a temp folder or even in Java's cache.
Also, the applet constantly cleared the windows clipbrd so Print Screen didn't work.
It worked pretty good, but it had some faults.
Besides requiring Java, the JS that embedded the applet (and maybe the applet itself) was setup to not load properly in any browser that didn't give access to the windows clipbrd. This meant that it only worked in IE and only on windows.
Also, the interval the applet used to clear the clipbrd could be beaten with a really fast Print Screen and ctrl+v into Gimp. Printing the screen in other ways would work too.
Finally, Jad could decompile the applet and all/most of its files. So, if you really wanted the pics, you could poke around in the source to figure out how they did it.
In short, you can go out of your way to stop a lot of people, but usability goes down the drain and there will always be a way to get the image if the visitor can see it.
Anything you send to the client is, like, on the client. Not much you can do about it besides making somewhere between "sorta hard" and "quite hard" to save the image.
I must say in the begining that it is almost impossible to stop the
images or text being copied, but making it difficult will prevent most
of the users to steal content.. In this article I will give a easier
but effective way of protecting images with html/css. We will take a
very simple way for this… Firstly in a div we will place the image
with a given height and width. (Say 200 X 200)
Now we can place another transparent image with same height and
width and give it a margine of -200. So that it will overlap the
actual image. And when the user will try to copy this, they will end
up with the transparent gif only…
<div style=”float: left;”>
<img src=”your-image.jpg” style=”width: 200px;height: 200px;”/>
<img src=”the-dummy-image.png” style=”border: 0px solid #000; width: 200px; height: 250px; margin-left: -200px; ” />
</div>