You're pulling logos out of a PDF brand guide. You convert to PNG expecting transparent backgrounds and get white instead. The PDF showed white because that's the page background, not the logo's actual edge.
PNG transparency vs JPG
PNG supports an alpha channel — pixels can be fully transparent, fully opaque, or anywhere in between. JPG has no transparency support; transparent areas become whatever colour the converter fills (usually white).
If you need transparency at all, PNG is your format. Don't bother with JPG.
Why your PNG isn't transparent
Most PDFs have an opaque page background — usually white. When you render a PDF page to PNG, the converter renders the visible page, including that background. The result is a PNG with no transparency, just a white block.
The converter is doing the right thing. The PDF doesn't have transparency to give.
Get the logo without the background
Two approaches. First, ask for the source. Brand teams usually have a transparent PNG or SVG of every logo. Always faster than extraction.
Second, convert to PNG, then remove the background in an image editor — Photoshop's Magic Wand, Preview's Instant Alpha on Mac, or remove.bg for fast jobs. Works well on logos with clean edges, less well on intricate ones.
If the PDF itself has transparency
Some PDFs use transparency for layered design effects. Flint's PDF to PNG preserves that transparency in the PNG output if it exists in the source. Most don't, though — page backgrounds are typically opaque.
FAQ
Does the converter add transparency?
No — it preserves what's in the source PDF. If the PDF has an opaque background, the PNG will too.
What's the alternative for logos?
Request the source SVG or transparent PNG from the brand team. Or remove the background after conversion.
Will edges be clean?
Yes — PNG handles sharp edges better than JPG. Anti-aliasing is preserved.
Is the file size bigger?
PNG is usually larger than JPG for photo content, similar or smaller for line art and text.
PNG for transparency, JPG for photos. Convert your PDF to PNG and remove the background if needed.