editted twentyten doesn't align post

That is not the original Twenty Ten theme. It’s a completely custom theme.

yes I editted the theme…build on the twentyten..

But the CSS is completely different and no longer bears any relation to the original theme. So it’s not a 2010 issue – it’s a CSS issue in your theme. Try using Firefox with the Firebug add-on for this kind of CSS troubleshooting. Or use whatever developer tool is available in your web browser.

a like that…then I will call it my theme ??
yes i used chrome with the element inspector..
It looks like he puts the ‘good’ images in a class.alignleft, but the wrong images don’t seem to be in any class, just <img…

I think this might be the problem…

How are you adding these images?

images: add media, upload files etc
video: copy the embed code <iframe etc then embed it in text

i added overflow:hidden to the #concent css
So it looks fixed, but it isn’t cuts away half of the video, but it’s something…

This is from Twentyten, and it is in your theme too.

img.size-auto,
img.size-full,
img.size-large,
img.size-medium,
.attachment img,
.widget-container img {
	max-width: 100%; /* When images are too wide for containing element, force them to fit. */
	height: auto; /* Override height to match resized width for correct aspect ratio. */
}

That’s what prevent too big images from not spilling out of the container. Images that get inserted into post content via WP media interface will get one of that .size-xx class and will be scaled down to fit.

So when you copy and paste <img> tag directly, just include a .size-full class in its attribute. Or write one more code in CSS targetting all images in content area #content img to have this same property.

For the video embed, the size is controlled by this in functions.php

if ( ! isset( $content_width ) )
	$content_width = 640;

Do you have this just like Twentyten has ? If so, when embeding a youtube video, just paste only plain txt url link to video.