PHP: if image exists show image else show different image

Just run it through the logic, using file_exists:

$image="/path/on/local/server/to/image/icon.png";
$http_image="http://whatever.com/url/to/image";

if(file_exists($image))
{
  echo "<img src=\"$http_image\"/>\n";
}
else
{
  echo "<img src=\"uploads/$username/noprofile.png\"/>\n";
} 

Check to see if the file has been uploaded by using file exists. If the file exists, use that url else use the default noprofile.png.

you could make a column in the DB to store a value if it has been uploaded or not.

OR

you could see if the file exists.

<?php
if (file_exists('uploads/' . $username . '/icon.png')) {
echo '<img src="uploads/' . $username . '/icon.png">';
}
else {
echo '<img src="uploads/' . $username . '/noprofile.png">';
}
?>

<?php

$img = file_exists(sprintf('/path/to/uploads/%s/icon.png', $username))
     ? 'icon.png' : 'noprofile.png';
?>

<img src="uploads/<?php printf('%s/%s', htmlspecialchars($username), $img) ?>">

You could use https://www.php.net/file_exists to check if the image file is there.

Another alternative is - assuming you keep your user info in a database - have a column with the image name. Since you have to retrieve info from your user table anyway, check to see if that column is NULL or blank. If it is, the user has not uploaded an image yet.

Then, in the page you display the user photo, you might have code something like this:

$userPhoto = ($photoName)? $photoName : 'placeholder';
echo '<img src="uploads/'.$userPhoto.'.png" />

Assuming the filepaths are correct, here's what you do...

<?php $filename = "uploads/".$username;    
$imgSrc = file_exists($filename) ? $filename : "uploads/noprofile.png"; ?>
<img src=<?php echo $imgSrc?>

Use onerror attribute in img tag

<img onerror="this.src= 'img/No_image_available.png';"  src="<?php echo $row['column_name '];  ?>" />