What causes "The region must fit within the actual image size" in Intervention/image?

Check $splFileInfo->isFile() before calling read() and reject directories early

Intervention/image · error · Intervention\Image\Exceptions\InvalidArgumentException

The region must fit within the actual image size

Error message

The region must fit within the actual image size

What it means

This FileNotFoundException means the path inside your SplFileInfo exists but is not a regular file: is_file() returned false, so the path most likely points at a directory (or a special filesystem entry like a FIFO/socket). The directory check (is_dir on the dirname) and file_exists() both passed before reaching this guard in filePathFromSplFileInfoOrFail(), so the entry is present on disk but is the wrong type.

Source

Thrown at src/Analyzers/AbstractPaletteAnalyzer.php:59

     * @return Generator<array<int, int>>
     */
    protected function sampleCoordinates(SizeInterface $size, ?SizeInterface $region = null): Generator
    {
        $region = $region === null ? $size : $region;

        $startX = $region->pivot()->x();
        $startY = $region->pivot()->y();
        $width = $region->width();
        $height = $region->height();

        // validate the region including its position, otherwise offset
        // regions would sample coordinates outside of the image
        if (
            $startX < 0 || $startY < 0
            || $startX + $width > $size->width()
            || $startY + $height > $size->height()
        ) {
            throw new InvalidArgumentException('The region must fit within the actual image size');
        }

        $totalPixels = $width * $height;

        $sampleRate = match (true) {
            $totalPixels <= 10000 => 1, // <= 10k pixels: sample all
            $totalPixels <= 100000 => 5, // 10k-100k: every 5th pixel
            $totalPixels <= 500000 => 10, // 100k-500k: every 10th pixel
            $totalPixels <= 2000000 => 20, // 500k-2m: every 20th pixel
            default => 30, // > 2m: every 30th pixel
        };

        $endX = $startX + $width;
        $endY = $startY + $height;

        for ($y = $startY; $y < $endY; $y += $sampleRate) {
            for ($x = $startX; $x < $endX; $x += $sampleRate) {
                yield [$x, $y];

View on GitHub (pinned to 5598b9e397)

Solutions

Check $splFileInfo->isFile() before calling read() and reject directories early
Inspect getPathname() output: if it ends up being a folder, append the intended filename segment
When iterating directories, skip entries where isDir() is true before processing

Example fix

// before
foreach (new DirectoryIterator($dir) as $file) {
    $images[] = $manager->read($file); // throws on subdirectories
}

// after
foreach (new DirectoryIterator($dir) as $file) {
    if ($file->isFile()) {
        $images[] = $manager->read($file);
    }
}

Defensive patterns

Strategy: validation

Validate before calling

if (!$splFileInfo->isFile()) {
    throw new \InvalidArgumentException(
        'Expected a regular file, got: ' . $splFileInfo->getPathname()
    );
}
$image = $manager->read($splFileInfo);

Type guard

function isRegularImageFile(\SplFileInfo $info, array $exts = ['jpg','jpeg','png','gif','webp']): bool
{
    return $info->isFile()
        && in_array(strtolower($info->getExtension()), $exts, true);
}

Try / catch

use Intervention\Image\Exceptions\FileNotFoundException;

try {
    $image = $manager->read($file);
} catch (FileNotFoundException $e) {
    // message contains 'is no file in directory' when the entry exists but is a folder
    if (str_contains($e->getMessage(), 'is no file')) {
        // path points at a directory: fix the path builder
    }
}

Prevention

Always build paths as dirname + DIRECTORY_SEPARATOR + explicit filename; never pass a bare folder
When iterating directories, filter with isFile() before feeding entries to the manager
Reject trailing-slash paths from user input

When it happens

Trigger: ImageManager::read(new SplFileInfo($dir)) where $dir is a directory like storage_path('app') (its dirname exists and the entry itself exists, but it is a directory); passing a path that ends without a filename (e.g. trailing slash stripped to the folder); a symlink inside the path resolving to a directory; passing an SplFileInfo for a Unix special file.

Common situations: Building paths dynamically where the filename segment is empty and the path collapses to a folder; user-submitted 'path' fields that are actually folder names; scripts iterating DirectoryIterator and accidentally feeding the current directory entry ('.') or a subdirectory to read(); symlinks in upload dirs pointing at folders.

Related errors

AI-assisted analysis of Intervention/image@5598b9e397 (2026-08-23). Data as JSON: /api/errors/686547cbbf23d223. Report an issue: GitHub.