512x512 image for the iPhone app - iphone

I am about to submit my first app to the iTunes App Store. The docs say that the application needs to be submitted with a "512x512 px, 72ppi, RGB, flattened, no transparency JPEG image".
I have a couple of questions:
RGB - what exactly does it mean in this context.
Flattened - does it mean that if I am creating the image in Photoshop, I should flatten all the layers? Doesn't saving to JPEG kind of imply that? Or does it mean something completely different.
No transparency - JPEG doesn't support it to begin with. What color should the background be then?

RGB means to ensure that you save the image as an RGB (rather than CMYK) JPEG. This is very likely to be the case already. (You can change the colour mode via the 'Image -> Mode' menu in Photoshop if you have the icon in the CMYK colour space for some reason. That said, all images destined for on screen usage should remain with the RGB colour space.)
As you say, directly saving as a JPEG (or doing save for web) will flatten the layers for you.
Whatever colo(u)r you want it to be. (i.e: It'll appear as saved.)
Hope that makes sense.

They're just being very verbose. Just send the jpeg(saved for web) and all those conditions will be satisfied.
If you made a transparent background it will render as white on a jpeg anyway.
don't worry. send it :)

Related

upload and preview as repeated background image

I am searching for a tool on web but didnt got any success their at all. I want to have something like upload and preview the image as background as repeated one or any other alternative...
I have this sample:
How can I preview and cut the image as a perfect background image as repeated one. Is it possible in Photoshop or in some similiar products?
The trick i have recovered is crop a part of the image in a big canvas of Photoshop and then making the deuplicate copies of the layers...
If the image seems like irregular it means the cropped image is wrong so you have to change with a other or larger part of the image...
If it is regular and doesn't cut at the side onto the edge, it means image is perfect making background repeated...
Thanks...

How to segment an image in iOS to remove background and retain the foreground picture

I need to segment an image in ios for a fashion app by keeping only the foreground image and removing all other background part of the image which should resemble like a tool for removing the background of images in various photo editing tools please help me.
General background subtraction is an unsolved problem, so getting perfect results is going to be a big effort. With that said, you can probably get close. Here are a couple of suggested avenues:
I am guessing that your app will place clothes on a human, or something of the sort. Instead of getting a perfect segmentation, run a person detector, remove all of the image except for the detected person, and fit a part-based human model to the remaining image. Then you have the pose of the person, and can do your image processing accordingly.
Allow the user to input some strokes from the foreground and some strokes from the background, and run a graph-cuts-based image segmentation algorithm on the frame.
Begin your process by having the user not be present in your video stream. From this, learn the background distribution (start with a simple histogram of background pixels, there are much more elaborate schemes but you need a starting place). Then, when the user enters the scene, create a binary image containing the connected components that don't fit into the learned background distribution. This will not be perfect, but you will start to see something close to a binary image where the white pixels are your user, and the black pixels are the background. Use morphology operators to join any large connected components that are slightly separated, and threshold your image to remove small noise in the image, from things like specular objects and illumination changes.
Like I said (and is mentioned in the comments), this is not an easy problem, but you can come up with a good approximation if you put some time into it. I suggest the third method I listed. It is achievable, and can be broken down into small parts so you can tell when you're making progress.
Good luck!

How to reduce filesize of gradient PNG?

I am trying to create a background image on a webpage, which is similar to the 404 page used on tumbler...
http://testing404image.tumblr.com/
Here we can see a PNG which is 1623*1064 pixels, yet appears reasonably smooth gradient wise.
The direct link for the image is
http://testing404image.tumblr.com/images/status_bg.png?2
When I try to create a similar PNG (different colors, but same size) in Photoshop CS4 for Mac, the resulting file ends up at > 400k, whereas tumblers is 90k
Ive tried playing with all Photoshop options, including reducing number of colors to 55, but I cannot get the image below ~240k.
Ive also tried various optimising tools such as ImageOptim (http://imageoptim.com/) but to no avail.
Are there any properties of this PNG which result in a such a low file size?
I tried using JPG, thinking its better suited to gradient images, but even a 100% quality JPG resulted in noticeable aliasing, which an identical content/size PNG didnt have.
Thanks for any advice
Hi there changed the colours with
Image > Adjustments > Hue/Saturation - In Photoshop CS4
and this is the result:
as you can see it's almost the same size (75k).
Try playing around under the
Image > Adjustments
to get the color you are looking for and save as png with NONE for interlace.
Photoshop is not very good with PNG: I simply opened and saved it with the humble xnView (maximum compression), and got 74K. You can also convert it to paletted-image, and do some extra little tuning - PNGoptim gives me a final size of 64.548. I would't expect anything much better than that, the image is just too big.
BTW, be aware that using a gradient that is so big and so smooth that it a digital image (with 8 bits per pixel) cannot represent it without some banding. That image is really oversampled (you could resample it at 25% or less and display it scaled, and the result would be basically the same)
The actual reason is the source image your looking to have a lower gradient quality than the one you are making.
Just uncheck the Dither option (from the top toolbar in Photoshop) when filling the gradient color. the quality and smoothness of the gradient is decreased and therefore you get a very smaller file sized PNG output.

iPhone transparent images rendering poorly

I'm developing an iPad application. I have been provided with a PNG image that contains some transparency - basically a drop shadow. The problem I'm having is that this is rendering poorly within the application, both on the device and in the sim.
I've made up some samples to illustrate. The first is how the image appears in the PSD (correctly that is). The second is how it appears on the device. You can see that the strip of shadow in the middle of the image is distinctly more yellow and poorly looking.
PDF http://www.aspyre.com.au/stackoverflow/photoshop.png On Device http://www.aspyre.com.au/stackoverflow/device.png
Any ideas what I'm doing wrong?
Edit: Links to files:
- PNG
- PSD
Edit 2: I've also tried pngcrush to remove the gamma, in case that was causing a problem, but no luck. Directions I followed were here: pngcrush
The reason you're getting a colour in your shadow is because the PSD's shadow layer is set to Multiply and has a colour in it. When you export it without a background, Photoshop is unable to multiply it to anything and just uses the layer as is. You need to grab the selection of the shadow layer, create a new layer, and fill that selection with black. Then set that new layer's opacity to something that mimics the old shadow.
Also I recommend you use Save-For-Web if you don't already. The colour-profile you use isn't much of an issue then as it will be stripped. However the point is valid that you want to be in sRGB when making iPhone/iPad graphics.
Link to your PSD adjusted: PSD
Common mistakes:
Your color space is non-standard. Either use no color space, or specify sRGB (strongly preferred).
You didn't save the PNG with gamma information included.
Without access to the actual files we're grasping at straws.. Maybe you have an 8-bit instead of 24-bit png?
For your shadow, use black instead of gray. Then adjust the transparency. That should fix it.
I had a similar issue that I resolved by disabling compression for an image. This is done in XCode by removing the .png extension. You can disable png compression for an entire project by editing the 'Compress PNG Files' project setting, but it is not recommended.
More details about Xcode PNG compression: http://iphonedevelopment.blogspot.com/2008/10/iphone-optimized-pngs.html

Why does UIImageView "darken"/saturate PNG images, and can I stop it?

I have a PNG file in a UIImageView, and next to that I have an EAGLView which displays the continuation of that same image (long story) as a texture, carved from the same original PNG. The point is, that these images, which should match up flawlessly, actually have somewhat differing color saturation.
Normally I'd blame my handling of the PNG texture load in GL, but when I hold Preview (with the PNG) up to the iPhone simulator, it's GL that's spot on, and the UIImageView that's wrong! It's taken the image and made it ever-so-slightly more saturated. The image view is opaque with 100% alpha.
I verified this on a clean UIImageView with another PNG file when put next to Preview.
Anyone know what's up?
If you are using Photoshop to save the png using the "Save for Web & Devices" tool, ensure the "Convert to sRGB" option is off and "Embed Color Profile" is also off. If you are using another editor, look for similar settings.
Read this, it will help explain better than I can.