A square thumbnail can make an orderly page and a rather different photograph. That is the first thing I would check before choosing a media gallery layout: what happens to the pictures when the layout gets hold of them? Grids, masonry arrangements, slideshows and large single-image views each offer a useful way through a collection. They also impose their own habits. Some encourage comparison, some preserve the shape of a frame, and some ask the viewer to surrender the pace. My preference is to begin with the photographs and work outward. The demo page for a gallery theme is allowed to look fabulous; your pictures still have to survive living in it.

Consider this photograph of the Blue Angels against an almost uninterrupted blue sky. Four blue-and-yellow jets gather in a tight diamond on the right side of the frame, banked so their wings and upper surfaces form an overlapping pattern. Their noses point left. Yellow markings draw bright lines along the fuselages and tips of the tails, while thin pale trails extend behind them. Part of another aircraft enters from the right edge. Above, below and especially ahead of the formation, the sky occupies a generous amount of space. The planes are the subject, but the empty area gives their direction somewhere to go. I would be reluctant to tidy that away simply because a gallery prefers matching boxes.
In a centred square crop, some of that forward space would disappear and the aircraft at the far right could be cut more heavily. A crop shifted towards the planes might make them larger and easier to recognise in a small preview, while changing the balance again. Neither version is automatically wrong. The problem begins when a crop chosen for a thumbnail becomes the only version a visitor ever sees. For this picture, I would want an obvious route to the complete frame. A useful preview can introduce the photograph without pretending to replace it.
An equal-cell grid is a sensible choice when people need an overview. It lets them scan a collection quickly, compare subjects and decide what to open. Product photographs, portraits made to a consistent brief and event thumbnails can all work well in such a layout. Uniformity gives the page a calm rhythm. But a grid of square cells asks a portrait, a wide scene and a near-square composition to occupy the same shape. You can crop them, or fit each full image inside the cell with spare space around it. I would happily accept a little spare space when the alternative is removing something the photograph needs.
A grid does not have to mean square tiles. A justified-row layout places pictures in rows of similar height while allowing different widths, so a landscape remains broad and a portrait remains narrow. This can be a good compromise for a collection with mixed orientations. The page reads in clear horizontal bands, and the photographs keep their proportions. Watch the final row, though. Some implementations enlarge a lone remaining image or stretch a small group into a surprisingly emphatic ending. A quiet detail picture can suddenly look as if it has been appointed chairman of the collection.
Masonry takes another approach: images sit in columns with varying heights, filling gaps as the page develops. It often accommodates portraits and landscapes without forcing a common crop, and its irregular rhythm can make a varied archive inviting to browse. I like it for discovery. I am less convinced when a precise sequence matters. A viewer may follow a column down while the editor expected them to move across, and the arrangement may change again on a phone. If one photograph needs to come immediately after another to complete a thought, give that relationship a clearer structure. Masonry can offer a pleasant wander, but a wander is not always the job.
Slideshow layouts give each photograph a more separate encounter. They are useful when a sequence deserves deliberate attention or when you want captions to accompany one image at a time. The cost is that much of the collection stays hidden until the visitor advances. Include a visible count, clear previous and next controls, and ideally a way to see the whole selection as thumbnails. Let people operate it with a keyboard. I would leave automatic advancement off by default. A picture may need two seconds or twenty, and the person looking at it is in a better position to decide than a timer.
A lightbox is a viewing layer rather than a complete answer to the layout question. A grid or masonry page can open images in a larger overlay, keeping the collection visible behind it or available when it closes. Done well, that gives you both an overview and a closer look. Done badly, it traps the viewer inside a dark screen with a faint close symbol tucked somewhere near a corner. The larger image should preserve the intended composition, the caption should be readable, and closing the view should return people to a sensible place in the collection. These small courtesies matter more than an elaborate transition effect.
Then there is the large-image editorial layout: one photograph at a time in the page, with text between images where it contributes something. It uses more vertical space and makes quick comparison harder, but it lets a sequence breathe. The Blue Angels image benefits from enough width to reveal the formation without losing the surrounding sky. A wider presentation also makes the partial aircraft at the right feel like a deliberate edge in the frame rather than an unexplained fragment in a postage stamp. Large does not have to mean edge to edge across every screen. The useful size depends on the picture, its resolution and the space the reader has available.
With mixed media, visual consistency needs a little flexibility. A video thumbnail should show that it is a video and indicate its duration; an audio recording needs an informative title and recognisable playback controls. Making every item resemble a photograph may create an attractive grid while concealing what happens when someone clicks. Our guide to media galleries versus photo galleries explores the editorial reasons for including those formats. Once they are included, the layout should help visitors choose how to engage with them.
Mobile viewing is where an arrangement reveals its real priorities. Three columns that look comfortable on a desktop can turn into tiny previews on a narrow screen. A one-column layout may show the pictures beautifully but leave someone scrolling through a long collection without an overview. There is room for both a compact browsing view and an enlarged image view, provided moving between them is straightforward. Check portrait and landscape photographs, long captions, opening and closing controls, and the position you return to after viewing an image. I would also check that pictures loading farther down do not keep shoving the page around while someone is trying to read.
For a small portfolio, I would usually begin with uncropped thumbnails or justified rows and a straightforward larger view. For a varied archive, a restrained masonry layout can make browsing enjoyable, supported by clear collections and useful titles. For a story in which order and context matter, I would choose an editorial sequence. A slideshow earns its place when the concentrated viewing experience is worth the extra navigation. These are starting preferences, not laws. The more revealing test is to put the same handful of difficult images into each option: a tall portrait, a wide scene, a frame with an important edge detail and a quiet photograph full of empty space.
Our guide to organizing a media gallery deals with helping people find the right collection and individual item. Layout takes over once they arrive. Here, the Blue Angels photograph and its original commentary offer a useful reminder that apparently unused space may already be doing something. You can make the planes fill a box, certainly. I would rather give the viewer a chance to see why the photographer left them room to fly.