PNG vs JPG vs WebP: When to Use Each Image Format
Lossy vs lossless compression, when transparency matters, and why WebP is replacing both PNG and JPG on the web.
Why does one photo stop you mid-scroll while another nearly identical shot feels forgettable? The difference is rarely the camera or the subject — it's how elements are arranged within the frame. Composition is the invisible architecture of an image, and designers have been refining the rules for centuries. Understanding these principles transforms how you see every photograph, magazine spread, and social media post.
Divide any frame into a 3×3 grid with two evenly-spaced horizontal lines and two vertical lines. The four points where these lines intersect are called power points — the spots where the human eye naturally lands first. Placing your subject on or near a power point instead of dead center creates tension, energy, and visual interest.
The rule works because centered compositions feel static and predictable. Shifting the subject to one-third of the frame introduces asymmetry, which the brain finds more engaging. A portrait with the eyes on the upper-third line. A landscape with the horizon on the lower-third line. A street photo with the subject at a left-third intersection, walking into the remaining two-thirds of empty space.
Before the rule of thirds, there was the golden ratio — approximately 1.618:1, represented by the Greek letter phi (φ). This proportion appears in seashells, flower petals, hurricane formations, and Renaissance paintings. When applied to composition, it produces a subtle spiral that guides the viewer's eye through the image in a natural, flowing path.
The golden ratio grid is similar to the rule of thirds but slightly off-center — the dividing lines sit at about 38.2% and 61.8% instead of 33.3% and 66.7%. In practice, the difference is small enough that many photographers use the rule of thirds as a quick approximation of the golden ratio.
The golden ratio connects to the Fibonacci sequence (1, 1, 2, 3, 5, 8, 13, 21...), where each number is the sum of the previous two. Magazine designers use Fibonacci-based column widths: a sidebar might be 3 units wide, the main content 5 units, and the total layout 8 units. The proportions feel harmonious because they echo the same mathematical relationship.
Professional magazine and web layouts don't freehand element placement. They use grid systems — invisible structures that align text blocks, images, and whitespace into a cohesive rhythm. The most common grids:
The purpose of every grid is the same: create visual consistency so the viewer's eye knows where to look next. Alignment builds trust. When elements snap to a shared grid, the entire layout feels intentional, even if the viewer can't articulate why.
Every platform dictates the shape of your content, and each ratio carries its own visual language:
Visual balance doesn't mean symmetry. It means that the visual weight of elements is distributed so nothing feels like it's about to tip over. Several factors affect visual weight:
Composition is not about following rules mechanically. It's about understanding why certain arrangements resonate with human perception — then using that knowledge to make deliberate choices. The grid is a scaffold, not a prison.
Lossy vs lossless compression, when transparency matters, and why WebP is replacing both PNG and JPG on the web.
What happens when you drag the quality slider, how DCT transforms photos, and why screenshots compress differently.
How QR encodes data in binary modules, why error correction lets you put logos in the center, and what those corner squares do.