['required', function ($attribute, $value, $fail) { if (! preg_match('/^data:image\/(\w+);base64,/', $value)) { $fail('The '.$attribute.' is not a valid image.'); } else { $imageData = explode(',', $value)[1]; $image = base64_decode($imageData); $imageInfo = @getimagesizefromstring($image); if ($imageInfo === false) { $fail('The '.$attribute.' is not a valid image.'); } } }], ]; } }