A TikTok photo post is not a video that happens to show pictures. It is a genuinely different content type, stored as a set of individual JPEG files with a separate audio track, assembled into a slideshow by the app at playback time. That distinction matters, because it explains why so many downloaders handle these badly: a tool that assumes every TikTok link is a video will grab the first frame of the rendered slideshow and hand you one image out of a set of fifteen.
You can tell the two apart from the URL. Video posts contain /video/ in the path; photo posts contain /photo/. Short vm.tiktok.com and vt.tiktok.com links hide this until they are resolved, which is why the post type here is detected after the link is expanded rather than guessed from its shape.
One genuinely useful difference in your favour: slideshow stills are stored without the moving username watermark that TikTok burns into video frames. The images come back clean, with nothing to crop and no overlay drifting around the picture. This is the one TikTok content type where watermark removal is not a consideration at all.
The soundtrack is worth understanding too. Because it is stored as a separate file rather than mixed into anything, you can take the images without the audio or the audio without the images. Bear in mind that TikTok sounds are very often licensed commercial music, so while saving one for personal reference is ordinary, republishing it is a rights question independent of how the file was obtained.