Start with the problem you want to solve
A small image can be sharp; a large image can be blurry. Upscaling addresses dimensions, while enhancement aims to improve the perceived quality of the image. Focus, exposure, compression and subject texture affect quality even when the pixel count stays the same.
If the subject is already clear but the file is too small for its destination, consider enlargement. If your photo is mildly soft at its current size, try enhancement first. Severe blur may remain regardless of the number of output pixels.
A larger side means a much larger file
At 2×, an image that is 1,000 × 750 pixels becomes 2,000 × 1,500 pixels. Width and height double, but the number of pixels quadruples. At 4×, the output contains sixteen times as many pixels as the source.
That matters for processing limits, memory and credit costs. Read the actual output dimensions before starting instead of choosing the biggest label. Free Standard stays within a longest side of 1,024 pixels, so an upscale request may be capped by that boundary.
More pixels do not establish more information
A conventional resize interpolates between existing pixels. An AI model can also estimate patterns and textures based on learned examples. Either approach can make an image easier to display, but estimated detail is not a record of what the camera failed to capture.
Compare both versions at the same display size. Check letters, faces and material texture rather than judging only the impression from a thumbnail. If a pattern changes, decide whether the new version is appropriate for the purpose.
Choose dimensions for the destination
For a website, the display size and density of the screen matter. For print, the physical dimensions and viewing distance matter too. A pixel count alone cannot guarantee that a print looks sharp.
Use the destination's requirements, preview at the intended size where possible and keep the original. A large poster viewed from across a room has different needs from a small photograph examined close up.
Use a different method for pixel art and vectors
Vector artwork can usually be exported at a new resolution from its source application. Pixel art is deliberately built around a fixed grid; smoothing and generated texture can break its visual design.
Use integer nearest-neighbor scaling for pixel art. Each source pixel becomes a block of the same color. The local pixel art upscaler keeps that grid and transparency, while a general photo model may invent detail between the original pixels.