How WP-ImmoMakler Processes Property Images

When WP-ImmoMakler imports properties — for example from ImmoScout24 — the original images are transferred in full resolution, at around 4032×3024 pixels straight from the camera. Since such large images are not suitable for every view on the website, WP-ImmoMakler automatically scales each image into four smaller sizes, optimized for the list view, gallery thumbnails, gallery slider images, and larger list displays.

Image Quality During Import

You set the compression quality for the JPG/PNG image sizes generated during import in your website’s backend (wp-admin) under WP-ImmoMakler → Settings → Import → “Image Quality During Import”. The default value of 82 matches the WordPress default and offers a good balance of image quality, file size, and import speed. Lower values produce smaller files and speed up the import; very high values (above 90) noticeably slow down the import and significantly increase file size without a visible quality gain. The setting only affects future imports — already imported images remain unchanged.

For the optional AVIF conversion, there is a separate setting “AVIF Conversion Image Quality” right below it. The AVIF quality scale does not correspond to JPEG’s: AVIF already achieves very good rendering at noticeably lower values. The default value of 60 delivers high image quality at roughly half the file size compared to the value 82 — this reduces the amount of data transferred and improves your website’s PageSpeed Insights score. Higher values significantly increase AVIF file size without a visible quality gain.

For the optional WebP conversion, there is a corresponding setting “WebP Conversion Image Quality”. The WebP quality scale roughly matches JPEG’s, which is why the WordPress default value of 82 is used here — even so, WebP files come out noticeably smaller than JPG at the same value.

AVIF or WebP — Which Is Better for Property Photos?

WP-ImmoMakler can convert your property photos to a modern, smaller image format during import. WordPress handles this itself, so there’s no dependency on paid plugins. You select the target format in your website’s backend (wp-admin) under WP-ImmoMakler → Settings → Import → “Convert Property Photos to”:

WebP — the default. Typically 25–35% smaller than JPG and with more detail sharpness than AVIF. Usually the better trade-off for property photos. Requires WordPress 5.8 or newer.
AVIF — the smallest files (up to 70% smaller), but with slightly less detail sharpness. Well suited for design elements or corporate photos, and the right choice when file size matters more than detail sharpness. Requires WordPress 6.5 or newer.
No conversion — the image sizes stay JPG or PNG.

The conversion applies exclusively to JPG/JPEG and PNG property photos and only affects future imports — already imported images remain unchanged. You control the sharpness via the quality setting that belongs to the format — “WebP Conversion Image Quality” or “AVIF Conversion Image Quality” (see above): higher values deliver more detail sharpness at the cost of larger files.

Your server also needs to be able to write the chosen format (ImageMagick or GD with the corresponding support). A format your server can’t write isn’t offered in the selection at all — directly below the selection it then explains why it’s missing.

Contact Photos When Switching Formats

Photos of contact persons are normally skipped on re-import as long as the image file hasn’t changed. If you turn the conversion on again or switch formats, WP-ImmoMakler detects that an existing contact photo is still in the old image format and re-imports it once on the next import — so contact photos and property photos end up in the same format. This happens exactly once per photo, not on every import.

Image Optimization via Plugins

For the actual image optimization — i.e. reducing file size — WP-ImmoMakler relies on WordPress standards. This means that all common image optimization plugins work seamlessly with WP-ImmoMakler and can generate additional formats such as WebP or AVIF.

Avoiding Double Conversion

Once you’ve selected a conversion above, your property photos are already converted during import. If an image optimization plugin then also runs over the same files afterwards, that brings no further benefit: it compresses already lossy images a second time (which visibly degrades image quality) and unnecessarily burns credits with paid services like Imagify or ShortPixel — with several hundred properties at seven generated image sizes each, that quickly adds up to thousands of images per full import.

That’s why WP-ImmoMakler automatically excludes your property photos from the following plugins, as long as a conversion is selected: EWWW Image Optimizer, Imagify, Smush, and Converter for Media. This can be controlled via the “Exclude Property Photos from Optimization Plugins” option (default: active) — disable it if you want your optimization plugin to process property photos anyway.

Two cases can’t be covered via code and need an entry in the respective plugin’s settings:

ShortPixel doesn’t offer an interface through which another plugin can register exceptions.
Manual bulk optimizations that you start yourself in the optimization plugin — Imagify, for example, only honors exceptions for the automatic optimization of new images.

In these cases, add the directory /wp-content/uploads/immomakler/ to the exception or exclude list of the optimization plugin. All imported property photos live there; the rest of your media in the media library is unaffected and continues to be optimized.

What about the `<picture>` tag?

Some optimization plugins deliver modern image formats via a <picture> element that offers the browser a modern format and a JPG as a fallback. The exclusion doesn’t take anything away from you here, because a <picture> tag always needs two files: the modern image and an original to fall back to. WP-ImmoMakler’s conversion replaces the image sizes directly — so no JPG remains for a <picture> tag to reference. Optimization plugins therefore don’t generate a <picture> element for these images anyway, with or without the exclusion.

That’s not a drawback either: WebP and AVIF are displayed directly by all current browsers. A fallback would only matter for badly outdated browsers.

If you explicitly want such a fallback, the right setting is “No conversion” — then your property photos stay JPG/PNG, and your optimization plugin takes over the conversion along with <picture> delivery. Only then does an original actually exist as a fallback. Having both at once — our conversion and a fallback — isn’t technically possible.

Property Photos in the PDF Exposé

Converted images appear unchanged in the PDF exposé. WP-ImmoMakler automatically generates a JPG version internally for this and stores it in the PDF cache — necessary because AVIF and WebP can’t be embedded directly in a PDF. You don’t need to configure anything for this.

Customizing Image Sizes

The default image sizes are based on the display areas actually measured on customer websites. They form a ladder of 200, then 400, 475, 800, and 900, up to 1200 pixels wide (plus the original image). Between any two rungs the factor is never more than 2 — so the browser finds a suitable size for every screen width and pixel density, and never has to load an unnecessarily larger image.

Two special features of the ladder:

The height is always 1.5 times the width. These figures are pure upper bounds — nothing is cropped. Thanks to the higher upper bound, portrait-format photos and floor plans also reach the specified width; with square boundaries they would come out narrower and be upscaled blurrily in the display.
immomakler-archive-thumb-2x and immomakler-gallery-xl are not selectable display sizes but additional srcset candidates: they ensure that devices with high pixel density load a suitably sized intermediate variant instead of the much larger original image. immomakler-gallery-xl (1200 px) additionally serves as the social media preview image (see below).

To save storage space, you can adjust the sizes:

add_filter( 'immomakler_image_sizes', 'custom_immomakler_image_sizes' );
function custom_immomakler_image_sizes( $images_sizes ) {
  $images_sizes = [
    'immomakler-gallery-big' => [
      'width'  => 900,
      'height' => 1350,
      'crop'   => false,
    ],
    'immomakler-gallery-xl' => [
      'width'  => 1200,
      'height' => 1800,
      'crop'   => false,
    ],
    'immomakler-gallery-thumb' => [
      'width'  => 200,
      'height' => 300,
      'crop'   => false,
    ],
    'immomakler-archive-thumb' => [
      'width'  => 400,
      'height' => 600,
      'crop'   => false,
    ],
    'immomakler-archive-thumb-2x' => [
      'width'  => 800,
      'height' => 1200,
      'crop'   => false,
    ],
    'immomakler-archive-thumb-big' => [
      'width'  => 475,
      'height' => 713,
      'crop'   => false,
    ],
    'immomakler-person-thumb' => [
      'width'  => 400,
      'height' => 600,
      'crop'   => false,
    ],
  ];
  return $images_sizes;
}

Changed sizes apply to images imported in the future. Existing images keep their sizes until they are imported again or regenerated with a tool such as “Regenerate Thumbnails”.

Thumbnail Width in the List View

Which size the browser picks from the ladder is controlled by the sizes attribute. By default, the value calculated by WordPress is used, matching the requested image size — this usually matches the actual column width of the list view well.

If the list view is rendered in a noticeably narrower or wider column via a theme builder, you can determine the value yourself:

add_filter( 'immomakler_archive_image_sizes_attr', function () {
  // Example: from 992px screen width the column is 300px wide,
  // below that the card takes up 90% of the screen width.
  return '(min-width: 992px) 300px, 90vw';
} );

Width of the Images in the Image Gallery

For the image gallery, WordPress also calculates the sizes attribute from the requested image size. For the main image, that’s the immomakler-gallery-xl size at 1200 pixels — even if your theme displays the gallery narrower, for example next to a column of thumbnails. The browser then loads a larger image than necessary.

With the immomakler_gallery_image_sizes_attr filter you specify the actual width. Besides the value, the filter receives the image’s role (main for the main image, thumb for a thumbnail, tile for a tile in a grid or mosaic), the ID of the gallery layout, and the requested image size:

add_filter( 'immomakler_gallery_image_sizes_attr', function ( $sizes, $role, $preset ) {
  if ( 'main' === $role && 'vertical_thumbs' === $preset ) {
    // Example: up to 768px screen width the main image takes up almost
    // the full width, above that a 200px-wide column with thumbnails
    // sits on the right, and from 1320px the main image is 1070px wide.
    return '(max-width: 768px) calc(100vw - 40px), (max-width: 1320px) calc(100vw - 250px), 1070px';
  }
  return $sizes;
}, 10, 3 );

Return an empty value to keep the value calculated by WordPress. If the actual width falls between two rungs of the size ladder, the browser can only pick the next larger one — in that case, add a matching rung with immomakler_image_sizes (see above).

For the preview when sharing a property link (og:image), WP-ImmoMakler uses the immomakler-gallery-xl size at 1200 pixels wide — the value expected by Google, Facebook, and WhatsApp.

The image format matters here: WhatsApp does not render AVIF or WebP as a preview image, while Google handles them fine. WP-ImmoMakler therefore always delivers a JPG, PNG, or GIF as the preview image. If AVIF or WebP conversion is active on your website, a JPG version is automatically generated once and cached for the preview image — you don’t need to configure anything for this.

Which image formats are allowed as the preview image can be customized:

add_filter( 'immomakler_opengraph_compatible_image_types', function ( $types ) {
  return [ 'image/jpeg', 'image/png' ];
} );

The image size used can also be customized:

add_filter( 'immomakler_opengraph_image_size', function () {
  return 'immomakler-gallery-big';
} );

If you have any questions, please feel free to contact our Support.