Files and images#
Where what you upload is stored. Find it under Systém → Soubory and → Obrázky.
Images#
An image uploaded into the system is stored once, and thumbnails are produced from it automatically in the sizes needed.
Upload large, not pre-shrunk
The system shrinks what it needs. It cannot make a small image large — and it shows on a product detail or in a gallery.
Resized-copy sizes are set in the administration
Which resized copies get made from an uploaded image is decided by Image variants. A change applies only to newly uploaded images.
Images in the library#
In Systém → Obrázky images are uploaded to the library. The resized copies (variants) are not entered per image — a new file gets its variants from the Knihovna obrázků usage, set in Nastavení → Varianty obrázků → Použití (group Systém, see Images of the System module). A change there applies to images uploaded from then on.
The image edit form shows an overview of the variants the image has — a table with the columns Folder, Variant, Size (the file's actual size) and Original. It is read-only. Saving without replacing the file (say, only changing the title or description) does not change the variants; they are made again only when you upload a new file. An old record without variants shows a message that the image has no variants yet.
Formats and size#
| Format | When to use it |
|---|---|
| JPEG | photographs |
| PNG | logos, images with transparency |
| SVG | icons and simple graphics |
| WebP | a smaller file at the same quality |
Do not upload photographs straight from a camera
A phone shot can easily be 8 MB. Even though it gets resized, uploading takes time and occupies space. Shrink photographs to a sensible size before uploading.
Maximum file size#
The upload box (on the website and in the administration) offers as the maximum file size the
smaller of these values: the application limit and the PHP server limits
(upload_max_filesize and post_max_size). The server rejects a file above its limit before
the system even gets to it, so a higher number would be only a promise. A file larger than that
limit is refused straight away on selection with a message that states the actual limit (for
example "2 MB").
If you need to upload larger files, ask the server administrator to raise both PHP limits.
Maximum image size#
A photo may have at most 40 Mpx (for example 8000 × 5000 px). The real ceiling, however, also depends on the memory the server has for image processing: with the common PHP memory limit of 128 MB, images up to roughly 12 Mpx get through — a 6000 × 4000 px photo is therefore refused. If you want to upload larger photos, ask the server administrator to raise the memory limit.
An image that is too large is refused with a message: on the site the visitor sees it right while uploading; in the administration such a file is skipped on save and the others are saved. A warning at the top lists the skipped files and the reason (see Working with forms).
Camera data (EXIF) is removed#
On upload the system rotates the photo according to the camera data (so it is not lying on its side) and saves it without EXIF metadata. GPS location, phone model and capture date disappear from the photo. This also applies to users' profile photos. GIFs are the exception and are stored unchanged.
Video#
A gallery video must be MP4 or MOV and contain a video track. The system checks
this with the ffprobe program, which must be installed on the server (the ffmpeg
package). Without it the video is not uploaded — the file is refused and images keep
working. If videos cannot be uploaded, ask the server administrator to check ffprobe.
Files#
Files for download — manuals, price lists, documentation.
| Field | Note |
|---|---|
| Path and name | where it was stored |
| Extension | |
| Description | per language |
| Uploaded on |
An uploaded file is publicly accessible
Anyone who knows the address downloads it — without logging in. Do not upload anything that should not be public: price lists for selected customers, contracts, data backups.
What the file manager guards#
| File | What happens |
|---|---|
| SVG | cleaned before saving: scripts and other active content are removed, only the drawing remains. An SVG that cannot be cleaned is refused. Compressed .svgz is not accepted |
| HTML, XML, JavaScript | saved, but the browser offers them to the visitor as a download instead of displaying them |
hidden files (the name starts with a dot, such as .htaccess) |
cannot be deleted or renamed in the manager — they belong to the server configuration |
Naming#
No accents, no spaces
cenik-2026.pdf, not Ceník 2026 (finální).pdf. The name becomes part of the
address, and accents and spaces cause trouble there — especially in links sent by
email.
Put the date in the name
cenik-2026-01.pdf says at a glance whether it is current. Without it there is no
telling.
Replacing a file#
A new file under the same name may not show up immediately
Browsers remember downloaded files. So upload the new version under a new name and switch the link over.
Deleting#
A deleted file disappears from everywhere it is linked
The links do not disappear — they simply stop working. Before deleting anything, check where it is used.
Move unused files rather than deleting them at once
Rename them or move them to a separate folder and wait a while to see whether anyone speaks up.