Image size question

That depends. What is being used in both templates to call the relevant image?

esmi, thanks for replying. Here we go:

in home.php:

<?
		if($post_image !== '') {
		// display the image, its alt text, and wrap it with a link to "single.php" ?>
		<div class="imgleft" >
			<a href="<?php the_permalink(); ?>" title="<?php if($post_alt !== '') echo $post_alt; else the_title(); ?>">
			<img src="<?php echo $post_image; ?>"
			alt="<?php if($post_alt !== '') echo $post_alt; else the_title(); ?>"
			 style="width:250px; " /></a></div>

in single.php:

<img src="<?php echo $post_image; ?>"
	alt="<?php if($post_alt !== '') echo $post_alt; else the_title(); ?>"
	class="left" width="250px" />

I would like the image (uploaded original in more than 1000 px wide) to be repeated on single.php to be about 900 px wide.

Try:

<img src="<?php echo $post_image; ?>"
	alt="<?php if($post_alt !== '') echo $post_alt; else the_title(); ?>"
	class="left" width="900px" />

in single.php.