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Is it possible to interlace every image on my website?

I am creating a website which contains posts. Every post has an image. Feed page of the website is slow because every image takes a lot of time to be downloaded and while it is downloading it is a blank space and it does not look nice. Images are uploaded by users and are of different formats. Is it possible to somehow make it so that images first appear blurry and then they start becoming less and less blurry as they load (I’ve read it is called interlacing)?
I have tried searching on the internet but didn’t find anything on the topic but the usage of .jpeg format which does not seem to work because even the .jpegs I have as post images are not loading interlaced and I cannot exactly force people to use only that format.

Images take time to load because they are relatively large files and the data in them has to be transferred over the network.
Interlacing is a a feature of the JPEG format that gives visible process as the image loads by reordering the image data so it doesn't run sequentially (Wikipedia has diagrams and animations which might be helpful in understanding that.)
If you want interlacing in the image then you need to make sure it is in the image. You can't really change that outside the image.
While it is impractical to ask users to upload images encoded that way, you can write server side code to convert images to meet you standards. When converting them you could also perform other optimisations (such as reducing the dimensions or increasing the compression level) that would speed up the load time. Of course, this will have an impact on image quality which might not be desirable. (Consider Flickr, for example, which provides a degraded image (with smaller file size) by default but allows switching to higher quality or original images on demand).
You could also consider displaying placeholder images while the full version loads. These could also be generated server side from the upload images and have extremely high levels of compression and resizing so you just display a small number of large pixels that give a vague impressions of the average colour over large chunks of the image until the real image is available to the browser.

Showing a page content at once

I have a website which contains some images in index.php
The problem I am facing is the whole page is not loading at once, I think images are taking some time to load
So what I have done is, I am showing an loading image at first and then after some time I am showing the page, that resolves the problem. But I am curious to know is there any other better way to do this?

I prefer to optimise the hell out of my images.
PNG images
You can use pngcrush to optimise your PNG files for you, but personally I find that once I'm done with it pngcrush only succeeds in making it bigger.
Use Indexed-PNG wherever possible. This will limit you to 256 colours, and most graphics editors won't allow partial transparency in Indexed-PNG (but it is possible - you just need the right editor. I use a custom PHP script with the GD image library) but you can expect to drop file size down to just a tiny fraction of what it was.
Reduce the amount of colours overall. PNG compression works best with blocks of the same colour, so reducing the number of colours improves compression.
GIF images
Especially for animations, there's a lot of things you can do.
Reduce the number of frames. Avoid duplicate frames at all costs, and just set the previous frame to have a longer display time.
Use combine rather than replace if possible. You will again have problems with transparent areas, but by using combine you can have each subsequent frame only change the stuff that... changes. This avoids the redundancy of re-writing the entire image if only a small part changes. GIMP has a useful filter "Animation > Optimize for GIF" which will do this for you.
Reduce colours as much as possible. GIF is limited to 256 colours, but if you can limit yourself to 32 or so, you'll get a much smaller file.
Using the above techniques, I once managed to shove 8MB of raw image data into a 125kb animated GIF.
JPG images
JPG is great for photos, but cameras have a tendency to write MASSIVE files.
Play around with the compression factor. Start at around 40%, and slowly bring it up until it looks acceptable. GIMP will show you a preview and the resulting filesize, so make use of that to find an acceptable compromise.
Scale the image down. You don't need 9 megapixels or however massive resolution cameras take now...
The above should help you reduce the amount of size taken by your images. Obviously, you should also cache images appropriately, so they only need to be retrieved once. Also make sure that you specify width and height on image elements so that the browser can reserve the space for them and avoid jumping around as they load...
And you should be pretty good.

It's hard to say what other options are available without knowing what the page looks like, but one option is to reserve space for the images so that the page text renders quickly in the correct position, and the images then load later.

Javascript runs slowly in Safari / iPad2 after loading 200mb worth of new Images(). Why might this be?

Does anyone know why Javascript performance would be affected by the loading of lots of external JPG/PNG images into HTML5 Image() objects, totalling approx 200Mb-250Mb. Performance also seems to be affected by cache. Ie. if the cache is full(-ish) from previous browsing the performance on the current site is greatly reduced.
There are 2 says i can crudely solve it.
clear cache manually.
minimise browser, wait about 20 secs and re-open the browser after which time the iOS/browser has reclaimed the memory and runs the JS as it should.
I would have expected the iOS to reclaim required memory to run the current task, but it seems not. Another workaround is to load 200Mb of 'cache clearing' images into Image() objects, then remove these by setting the src = "". This does seem to help, but its not an elegant solution...
please help?

First and foremost read the excellent post on LinkedIn Engineering blog. Read it carefully and check if there are some optimizations that you can also try in your application. If you tried all of them and that still haven't solved your performance issues read on.
I assume that you have some image gallery or magazine-style content area on your page
How about having this image area in a separate iframe? What you could do then is this:
Have two iframes. Only one should be visible and active in time.
Load images into first iframe. Track the size of loaded images. If exact size tracking is hard
numberOfLoadedImages * averageImageSize
might be a pretty good aproximation.
As that number approaches some thresshold start preloading the currently visible content into second iframe.
Flip the visibility of iframes so the second one becomes active.
Clear the inner content of the first frame.
Repeat the whole procedure as necessary.
I don't know for sure if this would work for you but I hope that WebKit engine on iPad clears the memory of frames independently.
EDIT: It turned out you're writing a game.
If it's a game I assume that you want to have many game objects on the screen at the same time and you won't be able to simply unload some parts of them. Here are some suggestions for that case:
Don't use DOM for games: it's too memory-heavy. Fortunately, you're using canvas already.
Sprite your images. Image sprites not only help reducing the number of requests. They also let you reduce the number of Image objects and keep the per-file overhead lower. Read about using sprites for canvas animations on IE blog.
Optimize your images. There are several file size optimizers for images. SmushIt is one of them. Try it for your images. Pay attention to other techniques discussed in this great series by Stoyan Stefanov at YUI blog.
Try vector graphics. SVG is awesome and canvg can draw it on top of canvas.
Try simplifying your game world. Maybe some background objects don't need to be that detailed. Or maybe you can get away with fewer sprites for them. Or you can use image filters and masks for different objects of the same group. Like Dave Newton said iPad is a very constrained device and chances are you can get away with a relatively low-quality sprites.
These were all suggestions related to reduction of data you have to load. Some other suggestions that might work for you.
Preload images that you will need and unload images that you no longer need. If your game has "levels" or "missions" load sprites needed only for current one.
Try loading "popular" images first and download the remaining once in background. You can use separate <iframe> for that so your main game loop won't be interrupted by downloads. You can also use cross-frame messaging in order to coordinate your downloader frame.
You can store the very most popular images in localStorage, Application Cache and WebSQL. They can provide you with 5 mb of storage each. That's 15 megs of persistent cache for you. Note that you can use typed arrays for localStorage and WebSQL. Also keep in mind that Application Cache is quite hard to work with.
Try to package your game as a PhoneGap application. This way you can save your users from downloading a huge amount of data before playing the game. 200 megs as a single download just to open a page is way too much. Most people won't even bother to wait for that.
Other than that your initial suggestion to override cache with your images is actually valid. Just don't do it straight away. Explore the possibilities to reduce the download size for your game instead.

I managed to reduce the impact by setting all the images that aren't currently in the viewport to display:none. This was with background images though and I haven't tested over 100Mb of images, so can't say whether this truly helps. But definitely worth of trying.

Efficient jQuery or HTML5 image slider

I have a friend that is making a portfolio site. He has some high res images that he would like to display. There will be multiple projects on one page, and several images per project. Because of this, he would like to reduce load time as much as possible, and also conserve system memory usage. That being said, he's afraid that a conventional jQuery slider will eat up too much memory if it's called multiple times on the same page. Also, to load all of the images at initialization is just not an option as this would create long load times. Does anyone know of any image sliders, either jQuery or HTML5, or both that can help with this?

before spending time searching for a good jQuery slider...
...start from the basis:
start following general web design best practices like theese
keep your web page under 100 KB and load fast ? (the more is less the more is better)
use CDN (Content Delivery Network) to store HD images.
load HD images only on-demand, do not preload them.
use compressed, converted (avoid png) and resized images to fit the slider container.
do not scale images with CSS or inline CSS. (neither server side)
make use of the Lazy loading design pattern. (if as you say there are lots of images and the page is going to be very long)

Reducing image loading times?

I was wondering if there is any other ways to compress my images or any script that would load the page faster / or the the images behind the scenes?
The site is very interactive and using very high quality layers of images for the main layout. I have already saved for web devices in Photoshop and re-compressed using ImageOptim, some are jpeg but the majority are png24 to maintain transparancy, they are all set in CSS.
I have used jpegs and css sprites where i can but there is one in particular of a tree illustration streching the full site length, that is really slowing up the loading time, is there any I could compress these images further or code them differently that I missed?
Any help would be great thanks!

You said you are spriting. That is good.
You can also use tools such as PNGcrush which attempt to make files smaller by dropping things such as meta data.
You should also send far distant expiry headers and use a cache breaker on your images, to ensure the images won't be downloaded again if unnecessary.

In Photoshop, choose file-> save for web, you will be able to find the best compromise between size and quality.

Do you really need the transparency there? PNG transparency is unsupported on some browsers and makes the page processing intensive and slow even on high end computers, depending on image size and quantity of layers. If you can show something of your site maybe someone can give more hints about how to optimize it.

You can compress them on the fly with Apache if that's your web server. One of many available articles on the subject: http://www.samaxes.com/2009/01/more-on-compressing-and-caching-your-site-with-htaccess/