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• HEIC写真をJPG・PNGに変換するには

  アプリやフォームで HEIC 写真を開けないときは、出力形式を選び、まず1枚を変換してダウンロード結果を確認してから、残りの写真を処理してください。

• 文書をアップロードせずにPDFを結合

  PDF 文書全体を指定した順序で結合します。ブラウザ内で選択ファイルを読み、新しい PDF を作るため、文書内容を処理サーバーへ送信しません。

• 住宅ローン返済額とPMIの見方

  米国の固定金利住宅ローンを USD と月次利息で試算するモデルです。融資見積もり、金融助言、PMI 解除の判断ではありません。表示言語を変えても国・通貨の前提は変わりません。

• 通常返済と追加返済を比較する

  同じ固定金利ローンで、毎月の追加元本返済がある場合とない場合を比較します。金額は USD、利息は月次です。モデルの確認用であり、個人への金融助言ではありません。

• Local PDF tools vs upload sites: privacy, limits, and when each wins

  Merging or splitting a PDF looks identical in a screenshot: pick files, click a button, download a result. Under the surface, upload-based converters and browser-local tools take different paths with your bytes, keep different logs, and fail in different ways. This guide compares those paths using Merge PDF and Split PDF on yirinhana.win as the local example, without pretending local tools can replace every server workflow.

• iPhone HEIC to JPG: AirDrop, Mail, and failure edges

  iPhone photos frequently leave the Camera Roll as HEIC. Windows PCs, many web forms and some mail clients still expect JPG. This guide covers system-side settings, a browser conversion on this site, and the failure edges—Live Photos, huge originals, unsupported variants—so you can pick a path that finishes instead of renaming the extension and hoping.

• JPG vs PNG vs WebP: pick the format before you convert

  Opening a converter before you know the target format wastes time and can add generation loss. Use this decision guide first, then jump to PNG to JPG, JPG to PNG, or the WebP tools only when the direction is clear.

• Shrink images so email and forms stop rejecting them

  Résumé photos, insurance claims and school portals often enforce size caps that phone cameras ignore. Effective compression is an order of operations—dimensions, quality, then format—not a single desperate slider. This guide uses Image Compressor and related converters with checks you can see.

• Convert HEIC and screenshots for job applications and forms

  Online applications, credential uploads and portfolio forms frequently reject HEIC or oversized PNGs with vague errors. This end-to-end path covers export, conversion, compression and optional multi-image PDFs so you submit a file the portal will accept—processed locally before the official upload.

• Merge PDFs in the right order without blowing file size

  A merge can report success and still be wrong: pages shuffled, an appendix missing, a file too heavy for email, or a quiet refusal of an encrypted source. This guide focuses on deliberate ordering, realistic size expectations and the checks to run after Merge PDF finishes—complementing the privacy-oriented combine guide with operational detail.

• Split a PDF and email the pieces without the attachment bounce

  Email systems often reject oversized attachments long before a PDF “looks” large by page count. Splitting into page ranges or single pages—and sometimes zipping outputs—keeps sends moving while the split itself stays in your browser. This guide covers limits, modes, local steps and what to do when pieces are still too heavy.

• Tool limits and edge cases: encrypted PDFs, large media, and browsers

  Most confusion clusters around a few boundaries: encrypted PDFs, heavy media engines, browser support, proving files stay local, how ads relate to privacy, and what translated UI does not replace. This FAQ collects those edges in one place.